ZF-6 oil

[Mystic ZR-1]

This has probably been covered many times somewhere on the site, but:
I'm rounding up the stuff I'll need to recommision the Z for the coming season. The FSM, pgs 0B-12 & 13, calls for SAE 5W-30 (GM PN 1052931 or equivalent) 4.4pt/2.1L, for the ZF 6 speed.
Castrol 10W-60 seems to be the Forum's choice.
What's best?
Thanks!

[FU]

Castrol 10W-60

[GOLDCYLON]

The ZFDOC reccomends the BMW oil which is the same oil as the castrol

www.zfdoc.com (http://www.zfdoc.com)

Q&A off the above site

(Q.) I just bought, at the local BMW dealership, 3 liters of the Castrol TWS 10W60 oil. I was surprised to see that it is motor oil. Not being a lubrication engineer myself, who did the investigation and determination that this product is compatible with and good for our ZF transmissions? Jim � Grand Sport Registry

(A.) Jim, the C4 Corvette ZF S6-40 6-speed transmission uses engine oil for lubrication. I was told by Jeff Henning, Warranty Administrator of ZF Industries North America, that Engineering of ZF Industries in Germany determined that the BMW imported Castrol (RS superseded by TWS) 10W-60 oil was the recommended alternative to the (GM P/N 1052931) factory-fill oil for use in the ZF S6-40 transmission. In effort to verify ZF Industries alternative lubricant recommendation, we ran our own test series on the BMW imported Castrol TWS 10W-60 oil. Independent testing of the transmission oil samples was sub-contracted out to CTC Analytical Services. The test series went as follows:
<1> Spectrographic analysis indicated that it is has full synthetic composition.
<2> After 2 hours of operation, approximately 100 miles, oil sample analysis tests indicated that the viscosity rating was reduced from 60 down to a 43 level. No need to worry, this is a normal occurrence for this heavier type of oil. I attribute this to microscopic-level lubricant-strand trimming through operational loading where all of the oil contents has been passed through gear pressure-loading regions at least a few times.
<3> At 200 miles, the viscosity level stabilized at a 42 level viscosity since the 100 mile oil analysis test results.
<4> At 5000 miles, the oil analysis test results indicated a 40 level viscosity.
The test-transmission was completely disassembled and checked for wear. There were no signs of carbon film like experienced with the factory-fill oil. The phosphor-bronze lined synchronizers had no glazing and experienced an average mass loss of approximately 4% based on reserve-wear-range mass equivalency between 0.062"(new) and 0.048"(spent)
gap wear/mass measurements.
<5> At 10,000 miles, the oil analysis test results indicated a 39 level viscosity.
<6> At 12,500 miles, the oil analysis test results indicated a 37 level viscosity.
<7> At 15,000 miles, the oil analysis test results indicated a 34 level viscosity.
The test-transmission was again completely disassembled and checked for wear. There were no signs of carbon film like experienced with the factory-fill 30 oil. The phosphor-bronze lined synchronizers had no glazing and experienced an average mass loss of approximately 17% based on reserve-wear-range mass equivalency between 0.062"(new) and 0.048"(spent) gap wear/mass measurements.
<8> At 15,000 miles the oil had enough phosphor-bronze particles suspended
in it that deposits began building up inside of the synchronizer sliding
sleeves from the normal centrifuge-like rotational occurrence.
In Conclusion, until someone invents a copper magnet, we recommend that the ZF S6-40 6-speed transmission oil be changed at 10,000 - 12,000 mile intervals so as to minimize the amount of deposits of the suspended spent synchronizer material from collecting in critical component contact surface areas

[vilant]

I used the Castrol TWS 10W-60, and everything is running like a well oiled machine;). Ordered it online from, think it was a BMW dealer, Turner Motor sports. Anyway, I could dig up the info if you want it.:cheers:

[scottfab]

This has probably been covered many times somewhere on the site, but:
I'm rounding up the stuff I'll need to recommision the Z for the coming season. The FSM, pgs 0B-12 & 13, calls for SAE 5W-30 (GM PN 1052931 or equivalent) 4.4pt/2.1L, for the ZF 6 speed.
Castrol 10W-60 seems to be the Forum's choice.
What's best?
Thanks!


I still use the original GM stuff.

[mike100]

I prefer the shift quality using Amsoil synchromesh. It is thinner if that bothers you, but I think it may be closer to the original gear oil weight.

[secondchance]

http://www.zf.com/na/content/en/north_america/corporate_na/products_services_na/replacement_parts_na/corporate_replacement_parts_us/passenger_cars_replacement_us/service_portfolio_pc_replacement_us/faq_pc_us/faq_pc_us.html

If you scrol down about half way it says:

What type of oil do I need to use in my ZF S6-40 Corvette transmission?ZF only recommends the following lubricant for S6-40 transmissions. The GM oil (available from GM with part number 1052931) and the Castrol Synthetic Formula RS 10W60 (available from BMW with part number 0751009420).What type of oil do I need to use in my ZF S6-40 Corvette transmission?ZF only recommends the following lubricant for S6-40 transmissions. The GM oil (available from GM with part number 1052931) and the Castrol Synthetic Formula RS 10W60 (available from BMW with part number 0751009420)."ZF only recommends the following lubricant for S6-40 transmissions. The GM oil (available from GM with part number 1052931) and the Castrol Synthetic Formula RS 10W60 (available from BMW with part number 0751009420)."

[MRC1994]

What is the capacity? How many quarts do I need?
Thanks,
Greg

[mike100]

What is the capacity? How many quarts do I need?
Thanks,
Greg

2.2 qts, but you need 3 bottles. Of course a little spills so you end up with 2/rds of a qt left over to use as a topper.

[MRC1994]

2.2 qts, but you need 3 bottles. Of course a little spills so you end up with 2/rds of a qt left over to use as a topper.

Thanks,:dancing
Greg

[PhillipsLT5]

sold in liters @ BMW dealer, not quarts

[sammy]

when i was @ bills in dec he had me try some new oil that rockland gear came out with called 150 SM transzilla lube . i like the way the trans works with this stuff over the castrol .jmho . might want to give him a ring about it .

[WVZR-1]

Yes, RSG has their own lubricants these days and the 150SM is on their application sheet for the ZF. Ironically the application guide calls for 4 guarts, and they're the ONLY distributor for our ZF parts in the country. Has it any advantages over any other synthetic? Likely not but I'd be pretty confident if you purchased any of their "custom build transmissions" it will certainly be the lube recommended and maybe required for warranty.

Everybody has their branded lubricants even Joe Gibbs.

I have GM original in the box but Castrol in the transmission. No particular reason except the Castrol was an alternative that was just being discussed when the I purchased the car. I've actually been inclined to maybe just use Mobil1 10W30 or another synthetic equal to it.

[alwayscode390]

Thanks for the heads up and part numbers, I will be swapping out the fluid in my Transmission in the upcoming month :) ---

[scottfab]

...snip....
I've actually been inclined to maybe just use Mobil1 10W30 or another synthetic equal to it.

There's been some pretty compelling evidence that using some synthetics in the ZF is a no no. I believe fried sychros are the result.
Ask around. This was a thread that went around on the list server (email threads) years ago. Why this happens with Mobil 10w30 and not the BMW 10w60 synthetic? dunno
Might want to ask Bill.

[WVZR-1]

There's been some pretty compelling evidence that using some synthetics in the ZF is a no no. I believe fried sychros are the result.
Ask around. This was a thread that went around on the list server (email threads) years ago. Why this happens with Mobil 10w30 and not the BMW 10w60 synthetic? dunno
Might want to ask Bill.

I believe that the issues were with the use of synthetics and other blends that were advertised as being gear-box applicable only. An example of this would be the earlier GM Syncromesh Fluid that is NOT an acceptable lubricant. I don't believe that was related to engine oil synthetics. Some of the "compelling" you mention I believe to be "I heard it on the Internet" sourced!

The other thought and it would make no difference I guess of the lubricant "of choice" is just do the change maybe at every third engine oil change to keep it fresh. I believe a good question related is how frequently or on what schedule do you do the ZF maintenance. The lubricant of choice get's "beat to death" and I believe the interval of service might likely be the more relative question.

[mike100]

when i was @ bills in dec he had me try some new oil that rockland gear came out with called 150 SM transzilla lube . i like the way the trans works with this stuff over the castrol .jmho . might want to give him a ring about it .

Is it thinner?

and Oh my say it isn't so! people actually using something other than the 10w-60!!!

[Hib Halverson]

The original GM lube for the ZF S6-40 was a Texaco 5W-30 engine oil, but it hasn't been available in many years. What GM sells now is a 5W-30 but it's not the same stuff.

Some like that BMW lube (the 10W60 engine oil) but some who've tested it say it needs to be frequently, like every 10,000 miles.

Back in the day, when the ZF was undergoing some racetrack development in the late 80s, the race teams which were assisting GM in testing it (Morrison Development and Bakeracing) put Red Line MTL in them. What works quite well.

The ultimate in ZF lubes, IMO, is Red Line Light Shockproof Gear Lubricant. I've been using it for about 15 years in two different ZFs and it works quite well...especially for shift feel and getting a slight reduction in gear rattle. I change it religiously every 36,000 miles and have a sample analyzed. Every time the analysis comes back ok. I have about 90,000 miles on a 95 using tghat lubricant most of the time and MTL the rest of the time.

[Hib Halverson]

There's been some pretty compelling evidence that using some synthetics in the ZF is a no no. I believe fried sychros are the result.
Ask around. This was a thread that went around on the list server (email threads) years ago. Why this happens with Mobil 10w30 and not the BMW 10w60 synthetic? dunno
Might want to ask Bill.

All B.S.

[A26B]

All B.S.

Hib, you always come up with an absolute, unequivocal statements that leave no margin for consideration of the actual experience of others.

To the other, more open-minded, reading and posting in this thread, I offer this information from personal experience, that my transmission seized up completely, shortly after draining the original transmission lube and replacing it with Redline synthetic.

In addition to my experience, a very good friend, Ron Hanselman, had the same seizure after replacing the factory lube with Redline.

Also, I spoke with Bill B. about it and he confirmed knowledge of another seizure, also after switching to Redline.

Now, for some it may take some long-haired, four-eyed, nearsighted engineer with a lot of abbreviations after his name to convince some people to reconsider using Redline synthetic in their ZF tranny, but not me.

So, allege BS if you want, but there is sufficient reason to cause at least 3 of us to discontinue the use of Redline in favor of the Castrol lube recommended by Bill B.

Respectfully,

[tomtom72]

sold in liters @ BMW dealer, not quarts

Maybe a minor point, but yes it is sold in liters and our transmission specs give the quantity in Liters also. 2.2 Liters is full, buy 3 Liters and you will have enough left over to do at least three or for more years worth just buying two Liters each time you go to the BMW dealer. The stuff is a bit pricy, but it is the dealership parts counter.

Oh, this is two more cents from the peanut gallery about the change intervals. The Owner's manual says 50k I think ( I read that and laughed! ) or maybe it said never and just top off as needed ( I might have choked ). Okay so I'm not from AAMCO, nor am I a Tech. I have rebuilt one manual in my life, an M22 back at the dawn of synthetic lubricant era. The owner's manual for my 72 LT-1 said if you had an M22, then every six months or 6K miles on the change interval. They were inexpensive boxes to buy and rebuild. I spent about $500 in parts and I had to buy a new input shaft, front bearing & center bearing, forks & a side cover & a reverse idler gear ( it had chips! ) besides the "small parts kit" which got you every roller, needle, and ball bearing and their cages and blocker rings. I ain't doing that again with the zf box as to my view the synchros are more complicated than an entire M22 box! Besides, wouldn't you like to keep that oil passage to the "extra" section where 6th & reverse lives open so oil can find it's way back there? Good idea, no? Remember our boxes were born as 5 spd truck boxes, so that oil passage, which Bill says is too small, needs to be kept clear ( clean ).:o sorry for the rant!

To me the question is what do you want to spend your money on after reading the info at Bill's site ( zfdoc.com ): changing the fluid every year? Two yrs? or having to pull the trans and either you rebuild it or send it out?
My answer still is, after looking at the FSM diagram of a zf6, "I'd rather spend the $40 or $50 every year and not take unneeded chances." JMHO:o Just read Bill's lube test report and remember the important thing is the suspended remains of the blocker rings and the rear oil passage has to be kept clear ( unless you have Bill do your box as he opens up that oil passage ). Again JMHO :o

:cheers:
Tom

[scottfab]

I believe that the issues were with the use of synthetics and other blends that were advertised as being gear-box applicable only. An example of this would be the earlier GM Syncromesh Fluid that is NOT an acceptable lubricant. I don't believe that was related to engine oil synthetics. Some of the "compelling" you mention I believe to be "I heard it on the Internet" sourced!

The other thought and it would make no difference I guess of the lubricant "of choice" is just do the change maybe at every third engine oil change to keep it fresh. I believe a good question related is how frequently or on what schedule do you do the ZF maintenance. The lubricant of choice get's "beat to death" and I believe the interval of service might likely be the more relative question.

I can't dispute the "heard it on the internet" theory. And yet those I heard it from I believed and still do. Why would they lie? I mean we're all just hearing all of this on the internet right now right?

I like your theory. I think I'll change the ZF oil more often but stay with one oil. It could very well be the act of switching oil that causes the problems. The bad news is I only have one more change left with the GM stuff. I rebuilt my ZF once before. I don't want to do it again.

In any event each of us are going to have to do what seems best to us. I do trust Bill B. He has no axe to grind on this and gets no advertizing kickback to one oil vs another. Anyone that recommends one oil over another but who has a financial steak in doing so should openly disclose that fact.

I know the short list of what I will NOT use:
Redline (shock or no shock proof)
Mobile 10w30 (good for engine though)

[Hib Halverson]

Hib, you always come up with an absolute, unequivocal statements that leave no margin for consideration of the actual experience of others.

To the other, more open-minded, reading and posting in this thread, I offer this information from personal experience, that my transmission seized up completely, shortly after draining the original transmission lube and replacing it with Redline synthetic.

In addition to my experience, a very good friend, Ron Hanselman, had the same seizure after replacing the factory lube with Redline.

Also, I spoke with Bill B. about it and he confirmed knowledge of another seizure, also after switching to Redline.

Now, for some it may take some long-haired, four-eyed, nearsighted engineer with a lot of abbreviations after his name to convince some people to reconsider using Redline synthetic in their ZF tranny, but not me.

So, allege BS if you want, but there is sufficient reason to cause at least 3 of us to discontinue the use of Redline in favor of the Castrol lube recommended by Bill B.

Respectfully,

Your respect is noted but, I will continue to "allege BS".

Here's the deal, Jerry....
Neither yours, Ron's or the anecdotal account which Bill gives of failures are backed up by any scientific failure analysis. The only evidence you offer is the transmissions failed shortly after a lubricant change to Red Line. Was any spectrographic oil analysis done? Without that, your just pissing in the wind, dude. Under what conditions was the transmission operating when they failed? In what condition was the transmission before the lubricant change? What level of wear was present at the time of the change? What exactly seized. Was it sixth gear?

in the mid-'90s I was hired by both "Vette" and "Corvette Quarterly" magazines to write technical articles about the ZF S6-40 six-speed manual. In researching those articles, I traveled to Michigan to interview GM engineers, one of whom was Bill Zabritski, a now-retired GM Powertrain Engineer who was the Chief Engineer for manual transmissions in the late-80s, 90s and early '00s and oversaw the ZF S6-40 development. Another was Jim Minneker who, back then, was the Corvette Powertrain Manager and, as the platform powertrain "guy" had responsibility for the six-speed manual. I also interviewed Kim Baker, who, during the latter parts of the ZF development was contracted to by GM to run the transmission in the road racing C4s he campaigned as a durability test. In this interview Baker told me Red Line MTL was the lube he used in those ZFs and Minneker confirmed that. Morrison Development used synthetic in the ZF, too, but, of course, it was a Mobil 1 branded product. Oh...but those are just cases where the people who engineered the transmission were speaking to a writer on the record. I supposed they all could have lied to me, but I doubt it.

As for evidence, I have plenty. Let's start with anecdotal...since you seem to like that kind of thing...since the late-90s, I've used two different Red Line synthetic gear lubes in ZF S6-40s, MTL and Light Shockproof. In 1999 or 2000 (can't remember exactly when) I took one of these ZFs over to Bill in Phoenix. It had been lubed with Red Line Light Shockproof its entire life. He and I disassembled it together. He told me the level of wear was so low, some of the parts measured as would new parts. You can ask him about this if you want. Based on that, I've continued to lubricate my S6-40s with Light Shockproof. The duty cycle has been high-performance street, a little racing and mostly in the desert southwest.

I have pages of spectrographic oil analysis of samples of Red Line lubricants which have been drained out of ZF S6-40s--typically I change lube at 3yrs/36,000 miles. They usually show low levels of wear metals.

If synthetic trans lubes are poor choices and cause failures, why have not the two ZFs I have failed? The one in my 95 has nearly 90,000 miles on it and almost all of those miles were on either MTL or LSP. In fact, let me ask you...if Red Line gear lubricants cause failures, where are the widespread reports of them? Why aren't scores of ZFs blowing up shortly after being switched to Red Line or other low-vis synthetic gear lube?

In addition, I use the same Shockproof lubes in Richmond six-speeds, GM NV3500 six-speed, TREMEC T56 six-speeds and TREMEC 6060 six-speeds. If those synthetic lubricants cause failures, why haven't all those transmissions failed too.

With due respect, Jerry, personal experience doesn't mean squat when you make statements like–Red Line lubes cause ZFs to seize.

Please post some evidence.

[ZR-1Mikko]

Just filled mine up with the Redline Lightweight. I will let you know how it goes as I put more miles on it...

[Z51JEFF]

Im using Amsoil,cant tell much of a difference between this and what was in there.What was in there,I havent got a clue but with 15,000 miles on the car I would think OEM.

[efnfast]

Also running Amsoil. Changed it when I bought the car. Don't know what the PO was running.

[A26B]

Your respect is noted but. I will continue to allege BS.
No surprise.


Here's the deal, Jerry....
Neither yours, Ron's or the anecdotal account which Bill gives of failures are backed up by any scientific failure analysis.
No, just empirical, i.e. driveline locked up & completely immobile, on the road.

The only evidence you offer is the transmissions failed shortly after a lubricant change to Red Line.
Evidence? I've never stated or even alleged that Redline was the cause of the failure, but rather stated the coincidental relationship of use to actual failures with very similar circumstances. Each reader can draw his own conclusion & decide if Redline has sufficient benefit to warrant use.

Was any spectrographic oil analysis done? Without that, your just pissing in the wind, dude.
Are you referring to the oil replaced with Redline or the Redline lube? Hib, spectrographic analysis is NOT going to provide an absolute, finite answer to the failure cause. It will provide elemental content of the sample provided.

Under what conditions was the transmission operating when they failed?
Mine: Slow town cruising. First noticed stopping at light. Nearly stopped, felt like light braking. Started home to check, never higher than 4th, symptom increased. About 3 miles from first notice, left stop sign, mujch worse & actually seized completely from about 25 mph in the road even before I could pull over. Wreckered home.

Rons: Driving at highway speeds, seized.

In what condition was the transmission before the lubricant change?
Mine: Working fine, no syncro issues or dragging, 1994 w/abt 57,000 miles. No maint history to indicate if trans had been serviced. OIl "looked new" when drained.

Rons: No problems noted, 1991 with under 30K miles if I recall correctly. It's been several years.

What level of wear was present at the time of the change?

As previously stated, both transmissions were working fine. The only indication of wear would have been the visual observation of particulate contained in, and the color of the drained oil. None was noted. Inasmuch as the transmissions were working perfectly, there was no need to perform a scientific analysis.

What exactly seized. Was it sixth gear?
My transmission is still in the crate, as it was removed. Ron's was rebuilt by Bill B. I don't recall exactly what Bill B. said the seizure was due to.


As for evidence, I have plenty. Let's start with anecdotal...since you seem to like that kind of thing...I've used two different Red Line synthetic gear lubes in ZF S6-40s, MTL and Light Shockproof, since the late-90s. In 1999 I took one of these ZFs over to Bill in Phoenix. It was lubed with Red Line Light Shockproof. He and I disassembled it together. He told me the level of wear was so low, some of the parts measured as would new parts. You can ask him about this if you want. Based on that, I've continued to lube my S6-40s with Light Shockproof. The duty cycle has been high-performance street, a little racing and mostly in the desert southwest.

I have pages of spectrographic oil analysis of samples of Red Line lubricants which have been drained out of ZF S6-40s--typically I change lube at 3yrs/36,000 miles. They usually show very low levels of wear metals.
I am glad you haven't experienced any problems. Repair is not inexpensive.


If Red Line trans lubes are poor choices and cause failures, why have not the two ZFs I have failed? The one in my 95 has nearly 90,000 miles on it and almost all of those miles were on either MTL or LSP. In fact, let me ask you...if Red Line gear lubricants cause failures, where are the widespread reports of them?
Hib, I never said Redline lubes "cause failures." I've simply made a statement about the occurrence of transmission seizure failures that were coincidental with the installation of Redline lube. Based on the known failures and my conversation with Bill B., I simply do not find sufficient benefit of using Redline lube to warrant even the low, known incident of failure which is coincidental (not anecdotal) to installing Redline lube.


In addition, I use the same Shockproof lubes in Richmond six-speeds and TREMEC T56es. If those lubricants cause failures, why haven't those transmissions failed too.
Beyond the scope of this discussion.

With due respect, Jerry, personal experience doesn't mean squat when you make statements like...Red Line lubes cause failures.
Hib, at least try to keep it real. Please re-read my un-edited post. You will note that I never made any such statement. Insofar a personal experience goes, for some of us with that experience, once is plenty, especially when there's no significant benefit to be gained.

If you are defending BS, fine but please quit generating it with false quotes.

[Z51JEFF]

Anybody looking to change the trans oil for the first time,there a trick to getting the right wrench to fit.I cant remember how short the overall length needs to be to get the ratchet-socket between the trans and tunnel but I can find my socket,wrench and measure the length.

[vilant]

Anybody looking to change the trans oil for the first time,there a trick to getting the right wrench to fit.I cant remember how short the overall length needs to be to get the ratchet-socket between the trans and tunnel but I can find my socket,wrench and measure the length.
Here you go.http://www.zr1.net/forum/showthread.php?t=4859&highlight=transmission+drain+plug
You need a 17mm hex. If it's too long cut it down w/ a bandsaw and lightly file the cut.

[ghlkal]

I think we all know this, but for future reference when somebody finds this thread ... (I don't think this was mentioned yet)

Be sure to remove the fill plug on the side of the ZF first. If you can't get that out, you won't be able to fill it. You don't want to have dumped all your fluid out the bottom only to find you can't refill it.


BTW, I find the discussion in this thread fascinating ...

[A26B]

..........as well as Oil Pan threads (and oil pan oil level sensor threads). I also use a bit of Permatex on both sides of gaskets for water pump, front cover, oil pan, and IH coolant Manifolds. Just so you know and to give scottfab and maybe Jerry something to debate (the Permatex habit I will NOT give up even though removing such gaskets is NOT fun) :D

Easy now Cliff, aka Permatex Kid! :) Maybe off-topic in this thread?..... I will wager there is already considerable Permatex endorsement in SOLUTIONS somewhere. Do you own stock in that stuff?:sign10:

[Mystic ZR-1]

This has probably been covered many times somewhere on the site, but:
I'm rounding up the stuff I'll need to recommision the Z for the coming season. The FSM, pgs 0B-12 & 13, calls for SAE 5W-30 (GM PN 1052931 or equivalent) 4.4pt/2.1L, for the ZF 6 speed.
Castrol 10W-60 seems to be the Forum's choice.
What's best?
Thanks!

Didn't expect this question to have the "legs" to drag out to 4 pages of posts???

OK, I'm gonna use Castrol TWS 10W-60 and maybe a dab of Permatex on the drain and fill plugs...

Thanks for the input!

[WVZR-1]

Didn't expect this question to have the "legs" to drag out to 4 pages of posts???

OK, I'm gonna use Castrol TWS 10W-60 and maybe a dab of Permatex on the drain and fill plugs...

Thanks for the input!

It actually might continue for four more! It seems you've made the decision and that's what needs to happen. There's likely many who have "changed" branding and "lubricant" several times. They very well might continue to "change" branding their next service. I mentioned a while ago I felt "frequency" is or maybe should be the primary "concern"!

[Hib Halverson]

I apologize to Jerry for generating a false quote.

I thought when he posted this….
(snip)

To the other, more open-minded, reading and posting in this thread, I offer this information from personal experience, that my transmission seized up completely, shortly after draining the original transmission lube and replacing it with Redline synthetic.

In addition to my experience, a very good friend, Ron Hanselman, had the same seizure after replacing the factory lube with Redline.

Also, I spoke with Bill B. about it and he confirmed knowledge of another seizure, also after switching to Redline.(snip)…he was saying that Red Line gear lubricants caused ZF S6-40s to fail.

As for spectrographic oil analysis, it's good for two things: 1) learning something about the condition of the lubricant at the time the transmission failed and 2) learning something about the amount of microscopic metal particles in the lube.

If you understand the condition of the lube, you sometimes have clues about why a component failed.

If you know how much "wear metals" are in the lube, that's also a clue as the cause of a failure.

For someone who wants to use an ester-based synthetic lube, among the Red Line products, MTL is the best all-round choice for a ZF. It's a 75W80 on the gear oil viscostiy scale or about a 5W30 on the engine oil viscosity scale and is rated GL4. It has the two main advantages that all ester-based lubes better film strength and superior performance at high oil temperatures.

For very severe duty, some folks, myself included, use Red Line Lightweight Shockproof gear oil. I got started using it with an experiment in trying to mitigate the ZF's gear rattle. It did reduce the noise, but it did not eliminate it. The Shockproof series of lubricants use a calcium-based EP additive package which has added advantages in cushioning gear teeth against each other and is why Shockproof seems to quiet the gear rattle a bit. Shockproof's gel-based technology has enhanced film strength–in this case it's similar to a 75W140 gear lube–but low flow resistance–Light Shockproof flows like an SAE30 engine oil. On the downside, some people aren't comfortable with Shockproof's consistency or it's color–Bill Boudreau calls it "Martian Blood". Also, unlike MTL, at low temperatures, transmissions using LSP will have higher shift effort until the lube warms a bit. It doesn't need to be at operating temperature, just warmed a bit and the shift feel improves significantly such that it is better than the old OE GM lube and other petroleum-based lubricants. So if you don't like the funkly blue color, you don't race your ZF and/or you drive in cool temperatures a lot, MTL is a better chocie.

As for tools to use to remove the drain and fill plugs, right after I bought my ZR-1 I got a "VW Transaxle Tool" which is basically, a 3/8-th drive bit assed hex key. I've used that and a long handle flex ratchet to R&R the two plugs. I think where some people get in trouble if overtightening those plugs which have pipe threads. They need to be tight, but not super tight because super tight makes them super hard to get out.

[Paul Workman]

At AutoZone I found a set of 3 short 1/2" drive hex "bits" in a set - one of them the 17mm needed for transmission.

first time I removed the drain plug on the Z's trans, I had to use a lenght of pipe on the 1/2" drive breaker bar to break it loose. I reinsalled it with some anti-sieze (sp?) and applied "just snug" torque with a standard 1/2" rachet. I've never had it leak, nor has there been any issues removing it since to change oil (per Bill B. @ approx 10k intervals (every 2 years for me).

FWIW,

P.

[Hib Halverson]

I've only worked on a few ZFs in my day but I've never experienced one with fill/drain plugs which are installed that tight.

No doubt, when they get that way, I can see the need for such big tools but I wonder how the plugs get that tight to begin with.

[A26B]

Thank you Hib, apology accepted. I knew when you re-read my post that you would see clearly that I never made such a statement. :handshak:

.......when you make statements like–Red Line lubes cause ZFs to seize.

[A26B]

first time I removed the drain plug on the Z's trans, I had to use a lenght of pipe on the 1/2" drive breaker bar to break it loose. FWIW, P.

I had the same experience on my 1994 Zee that had 57K when I acquired it.

I suspect galvanic weld but hesitate to even infer such a possiblity until I have acquired at least several hundred, fully documented and verified case histories, plotted the frequency and magnitude of the results, performed SEM and chemical analysis in a certified laboratory and consulted a registered professional metallurgist. Merely being very difficult to loosen is just a "personal experience" and "doesn't mean squat" you know.

[Gunny]

... I suspect galvanic weld ...

if it were a galvanic weld does that mean you bought the Z in Galveston, TX, Galva, KS, or Gálvez, Argentina? I figure they have good welding shops in TX & KS but have no knowledge of welding in Argentina.

[A26B]

if it were a galvanic weld does that mean you bought the Z in Galveston, TX, Galva, KS, or Gálvez, Argentina? I figure they have good welding shops in TX & KS but have no knowledge of welding in Argentina.

Might be! :sign10:

I thought they were wee li'l people that were invisible. Sorta like a leprechaun ya know, except the polish variety. http://i190.photobucket.com/albums/z224/A26B/file000MA13118317-0002.gif

[scottfab]

I had the same experience on my 1994 Zee that had 57K when I acquired it.

I suspect galvanic weld but hesitate to even infer such a possiblity until I have acquired at least several hundred, fully documented and verified case histories, plotted the frequency and magnitude of the results, performed SEM and chemical analysis in a certified laboratory and consulted a registered professional metallurgist. Merely being very difficult to loosen is just a "personal experience" and "doesn't mean squat" you know.

Yah, it's all just internet rumors until you get full documented and collaborated results that are traceable to the NBS (http://www.commerce.gov/blog/category/1950)

[Hib Halverson]

It’s been a while since I’ve been active on this thread. Since I last posted here, I’ve done some research and I'm continuing to research the lubricant issue.

First, I debunked the rumor Bill Broudeau, a long-time pal of mine in the Corvette hobby and who, of course, is the “AFDoc”, stated that Red Line Synthetic lubricants cause failures of ZF S6-40s. Bill and I discussed ZF lubricants and other six-speed issues via email for about a week and in that discussion he said...About seven years ago I had reservation about the wear in one particular ZF
I had in the shop which had been running Red Line MTL in it. A thread
spawned from that of which about a week later I publicly admitted as being
invalid.

You can quote me on the following...

These transmissions run great with any Synchromesh oil specified to replace
GM factory fill (discontinued P/N 12345349), Redline MTL and LSP as well as
ZF recommended Castrol TWS.

As for additional rumors that Red Line gear lubricants case ZF six-speeds to fail, I’ve yet to see any evidence of that, but I remain open-minded...if someone has proof, please post it. If there is no proof...enough already of the Red Line causes failures bull.

The original lubricant blended by Texaco and validated by GM for use in the original S6-40 and, then later, in the 2nd design, was a petroleum-based, API SF/SG 5W30 engine oil. It was selected by GM because it provided the required durability, had the best shift feel and, to help with fuel economy, had a low level of parasitic loss.

Interestingly, during the final part of the transmission’s development, GM hired Kim Baker’s race team to do some race track testing of the transmission. Baker ran the ZF in his Showroom stock race cars and lubricated the transmissions with Red Line MTL.

MTL is a low-viscosity, GL4-rated, gear lubricant which is a 75W80 on the grear oil viscosity scale or a 5W30 on the motor oil vis. scale. Compared to the factory fill 5W30, it offers as good or better shift feel, better reliability at high lubricant temperatures and/or higher-than-stock torque throughput and better durability.

Red Line Light Shockproof (LS) was developed long after MTL and is a synthetic gel-based gear lubricant having a calcium-based, extreme-pressure (EP) additive package. If flows like an SAE30 engine oil or an 80W gear lubricant but has the film thickness of a 75W140 gear lubricant. Once the lubricant is up to operating temperature, it offers better shift feel, better reliability and high lubricant temperatures and/or higher then stock torque throughput, better durability and slightly decreased gear rattle when the engine is at idle.

The different between MTL and LSP, in a practical sense, is that when the transmission is cold and in the early warm-up stage, LSP’s shift feel is not as good..mainly the shift effort is higher. This is because of LSP has higher viscosity at low temperatures than does MTL. So, given a street high-performance or racing duty cycle, if you use your ZF in cold weather, use MTL. If you don’t use it in cold weather or you’re willing to accept a little higher shift effort until the lubricant warms a bit, use LSP.

Now...Castrol TWS 10W60...
People love that stuff because 1) ZF suggests its use, 2) BMW uses it in some engines of its “ultimate driving machines” which, in the minds of many who are misinformed, makes it “wonderful”.

The facts is: in a ZF, it never will duplicate the shift feel of a proper low-viscosity gear lubricant because it’s twice the viscosity, i.e.: a 10W60 vs a 5W30.

My belief is ZF recommends TWS because, when confronted with GM discontinuing the lubricant which was originally approved for use in the S6-40 and not wanting to perform a costly durability test program with a new 5W30 lubricant, it picked a synthetic 10W60 figuring that doubling the viscosity requirement and using a synthetic base stock would cover its butt and, given proper drain intervals, from a durability standpoint, ZF likely made the right decision

There is evidence, resulting from some testing Bill Boudreau did, to support the belief that the Castrol TWS 10W60 is not very durable in its own right. That is: its viscosity is not consistent in service and changes somewhat rapidly such that by 10,000 miles, it should be drained. For more detailed information on TWS 10W60's viscosity change, contact the ZFDoc and ask about the TWS 10W60 test information.

Because of the inconsistent viscosity issue with Castrol 10W60, it seems foolish to buy an expensive synthetic 10W60 engine oil which you’d have to change three or four times in 3yrs/36,000 to 4yrs/48,000 miles when there are some other synthetic SAE30 (or 80-wt gear lubes) which can go far longer, both in time and distance, before they must be changed. Examples would be Red Line MTL and Red Line Light Shockproof. Also, for those who prefer brands other than Red Line, there may be other synthetic, 75W80, GL4 gear lubricants which would work well in a ZF.

I've used Red Line in both my ZFs. In my 95, I started with MTL and then, in the late-90s switched to LSP which, with 82,000 miles in the transmission, I continue to use, today.

I have a second ZF, a first gen unit for an L98/LT1, which was in another type of car for about 45,000 miles. When I got the trans, it had just been rebuilt by ZF and was shipped to me dry. That trans used Light Shockproof until the car was scrapped. I still have the trans in storage but it's for sale.

[Hib Halverson]

I have a half a case of Red Line Light Shockproof for sale.

Retail is $15.50@quart.

First, 40 bucks, plus shipping, takes it.

If you're interested email me at finspeed@netmotive.net

[mike100]

... there may be other synthetic, 75W80, GL4 gear lubricants which would work well in a ZF.



I have been considering trying Ford fully synthetic 75w-90 gear oil as it is definitely thinner than the bmw oil, but almost surely has a longer lifespan than the extra thin Amsoil synchromesh.

They use it in the current mustang and it shifts fine when warmed up. About $15 full retail at the dealer and in stock everywhere.

[Corbusa]

I am a Amsoil fan but the Trans oil to me seems a little thin .. I wonder what splitting the difference would hurt like Mobil1 15-50 ?
http://www.mobiloil.com/USA-English/MotorOil/Oils/Mobil_1_15W-50.aspx

[dredgeguy]

Any suggestions or thoughts of using Mobile 1 synthetic gear lubricants LS 75W-90?
One of the Corvette shops in Maryland recommended Royal Purple Synchromax synthetic oil.
Is one better than the other?

[WVZR-1]

Any suggestions or thoughts of using Mobile 1 synthetic gear lubricants LS 75W-90?
One of the Corvette shops in Maryland recommended Royal Purple Synchromax synthetic oil.
Is one better than the other?

Royal Purples own recommendation is NOT Synchromax See the GM 1052931 recommendation and I included the entire .pdf link also.

http://i1323.photobucket.com/albums/u595/wvzr-1/ROYALPURPLE_zpsce998d0c.jpg

http://royalpurpleconsumer.com/wp-content/uploads/Transmission_Lubricant_Cross_Reference_Chart.pdf

[Hib Halverson]

Keep in mind that the ZF S6-40 was designed to use a low-viscosity gear lubricant. The original factory fill was a 5W30 engine oil.

A 75W-90 gear oil, synthetic or other wise, or a 15W50 engine oil, synthetic or other wise, will likely be too high a viscosity and may cause poor shift feel, especially if the trans lube has not warmed to operating temperature.

With respect to synthetic lubricants, I don't think Mobil Oil makes a low-vis gear lube so you're going to have to look to one of the oil blenders which does. Look for something about 5W30 on the engine oil scale or about 70W80 on the gear lube scale. Also, avoid products which are rated GL5 and look for those rated GL4, which is the API rating for lubricants appropriate for spur- or helical-gear manual transmissions. GL5 is for hypoid rear axle gears.

With manual transmissions using cone synchros, the lube has to be blended with just the right level of extreme pressure (EP) additives–enough to promote good durability but not so much that synchro action is degraded. Hypoid gear sets, because the gear teeth slide across each other as they mesh, require higher levels of EP additives than do lubes for ordinary (ie: spur or helical) gear systems. Generally, GL5s have too much EP additive and that can inhibit synchronizer action in a manual transmission application

[RHanselman]

Hib,

I know your a fact guy and so am I, however...

Here's two data points with no backing what so ever but it's the reason I do not use RL:

#1
1991 ZR-1 w/4,500mi
Redline MTL with 1,200mi on the oil
High speed fun run 15 or so miles
Car began to slow rapidly and siezed to a stop at low speed
Resultant damage - ZF welded the reverse gears to the forward gear that's on the same shaft

#2
A close friend with a 94 ZR-1 experienced the same type of failure after switching to RL

Bill rebuilt my tranny and said he's seen others that have done the same on RL but he had no proof it was the oil. He just suspected there might be an issue...

Without any other way to verify/diagnose the actual problem that caused the failure the risk vs the reward of using RL again didn't pass the sniff test. It may or may not have had anything to do with the failure but like I said, sniff, sniff...

Just one man's reason... Right or wrong...

[dredgeguy]

Royal Purples own recommendation is NOT Synchromax See the GM 1052931 recommendation and I included the entire .pdf link also.

http://i1323.photobucket.com/albums/u595/wvzr-1/ROYALPURPLE_zpsce998d0c.jpg

http://royalpurpleconsumer.com/wp-content/uploads/Transmission_Lubricant_Cross_Reference_Chart.pdf

Looks like they sold me the wrong stuff, should have the HSP 10W-30 rather than the Synchromax.
Many thanks for the heads up.

[Corbusa]

Hey Dred Let me know how it works. You have my interest..

[A26B]

Hib,

I know your a fact guy and so am I, however...

Here's two data points with no backing what so ever but it's the reason I do not use RL:

#1
1991 ZR-1 w/4,500mi
Redline MTL with 1,200mi on the oil
High speed fun run 15 or so miles
Car began to slow rapidly and siezed to a stop at low speed
Resultant damage - ZF welded the reverse gears to the forward gear that's on the same shaft

#2
A close friend with a 94 ZR-1 experienced the same type of failure after switching to RL

Bill rebuilt my tranny and said he's seen others that have done the same on RL but he had no proof it was the oil. He just suspected there might be an issue...

Without any other way to verify/diagnose the actual problem that caused the failure the risk vs the reward of using RL again didn't pass the sniff test. It may or may not have had anything to do with the failure but like I said, sniff, sniff...

Just one man's reason... Right or wrong...

:cheers:Accurately stated. I corroborate the sniff test as well as Bill's comments which was not hearsay but told directly to me as well, just as you stated.

[Polo-1]

Agree
Don't use Red Line in the trans.

I did some high speed runs on the way home NM with the AB Z. The Red Line foamed and barfed out. The under side and rear bumper were covered in oil.

[Corbusa]

Anyone used this ? $75.00 TMD for 6
http://www.ebay.com/itm/EDM-GENUINE-TOTAL-ELF-10W-60-HIGH-PERFORMANCE-SYNTHETIC-OIL-M3-M5-M6-Z3-/261030875124?pt=Motors_Car_Truck_Parts_Accessories&hash=item3cc6a70ff4&vxp=mtr

[Polo-1]

have not tried that one.

I used GM, BMW/Castrol then Amsoil. Had the best shift feel with the Amsoil.

[Corbusa]

German Oil, BMW compat.
I would think synthetic 10w60 is basically the same BMW, Castrol, Total, or Liquid Moly. any thoughts ?

[WVZR-1]

German Oil, BMW compat.
I would think synthetic 10w60 is basically the same BMW, Castrol, Total, or Liquid Moly. any thoughts ?

I believe maybe "wrongly" but that's very far from being factual or close. If you had a vehicle that called for a Synthetic 10W60 and you needed to "top off" and had none of the correct fill I would guess you could "top off", the thought being something is better than nothing. The additive packages are what differentiate the products. Dramatically in some cases.

Regarding their use as a ZF fill who knows but I don't know why one would care to venture into products other than those that seem to have provided adequate or better performance characteristics for years. Those products seem to have survived the "time and mileage" test!!! If we were talking a product that required 5 - 7 quart fills maybe every 3 - 6K miles maybe there would be a cost justification but for a service that seems to do well at intervals that extend for some to 20K intervals why be concerned. I would think and I've mentioned before maybe it's not the product but the service interval that needs the attention. I would though I believe make my choice from the products with the track record that is now something near 20 years or so old. Just sayn'

[dredgeguy]

Hey Dred Let me know how it works. You have my interest..
Took back the Royal Purple and they gave me back my money. Said they use it for everybody but understand that us ZR-1 guys like to be difficult.
Now just need to find the right stuff to use!

[Dynomite]

for a service that seems to do well at intervals that extend for some to 20K intervals why be concerned. I would think and I've mentioned before maybe it's not the product but the service interval that needs the attention. I would though I believe make my choice from the products with the track record that is now something near 20 years or so old. Just sayn'

:thumbsup::handshak:

Just Do It ;)

Turner Motor Sports (http://www.turnermotorsport.com/p-1034-bmw-castrol-10w60-tws-synthetic-oil-e46-m3-e39-m5-e60-m5-e9x-m3.aspx)

Castrol 10W 60............17 mm Allen Wrench
http://i287.photobucket.com/albums/ll142/dynomite007/91%20ZR1/TWSCastrol-1.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/ZR1%20Maintenance/de90da95-206a-4b2d-95cc-cbaba81cf6d1.jpg

LT5/ZR-1 Fluids (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070550)

[Pete]

Just listen to Dynomite's solutions and you'll do fine.
Pete

[-=Jeff=-]

is this the AMSOIL some of you have been using?

http://www.amsoil.com/lit/databulletins/g2080.pdf

it does list GM 1052931 on the PDF

http://www.amsoil.com/shopres/products/270px/MTF.jpg

http://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-synchromesh-transmission-fluid-5w-30/

[dredgeguy]

Got the Castrol 10W-60 at the BMW dealer...painless

[alwayscode390]

So, the Castrol is the proven stuff ... the only issue is the low mileage maintenance requirements?

Whats some good stuff to use with higher mileage maintenance intervals? ---

[WVZR-1]

is this the AMSOIL some of you have been using?

http://www.amsoil.com/lit/databulletins/g2080.pdf

it does list GM 1052931 on the PDF

http://www.amsoil.com/shopres/products/270px/MTF.jpg

http://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-synchromesh-transmission-fluid-5w-30/

I noticed that maybe a week ago or so and I hadn't seen it in earlier. That .pdf is dated 7/12 and maybe it's actually just found it's way to the Internet and the previous versions didn't mention it. They actually only mention it by part # and there's no mention of the ZF S6-40 anywhere in the description. The GM applications mentioned are assemblies that always called for Synchromesh.

The only issue I've ever had with the MTF or any Amsoil product was the "shove" provided by most of the re-sellers. The implications of "by from me for 20% off and all that nonsense" is ridiculous. Check the other forum and it's generally "game on" to see who can post to an appropriate thread for any lubricant first.

I've plenty of the 1052931 and with the availability of other products I doubt I'd ever become an MTF user.

So, the Castrol is the proven stuff ... the only issue is the low mileage maintenance requirements?

Whats some good stuff to use with higher mileage maintenance intervals? ---

Why would you think the trans requires some "super extended higher mileage" intervals? It's less than 3 quarts of product. I wouldn't think the effort or the $$'s would create an issue for most!

[-=Jeff=-]

Yeah I too did not care for the AMSOIL push by some vendors at shows etc..

I did end up signing up for a preferred account on my own and I can pick up locally which is nice so then I can just get the Trans oil when I get my motor oil..

I did email Bill B regarding AMSOIl Synchromesh and this was his response:

AMSOIL Synchromesh oil is great oil to use in the ZF S6-40 transmission.

[alwayscode390]

Why would you think the trans requires some "super extended higher mileage" intervals? It's less than 3 quarts of product. I wouldn't think the effort or the $$'s would create an issue for most!

I don't think it requires that ... I just thought I read that using the Castrol required twice the maintenance than the factory scheduled maintenance intervals. Not that big of deal I guess , I don't put many miles on mine anyway ---

[Dynomite]

I don't think it requires that ... I just thought I read that using the Castrol required twice the maintenance than the factory scheduled maintenance intervals. Not that big of deal I guess , I don't put many miles on mine anyway ---

I think what Bill Boudreau was saying zfdoc questions and answeres (http://www.zfdoc.com/faq.htm) is that any ZF S6 40 transmission oil should be changed at around 10,000 - 12,000 miles :cheers:

Bill suggested........."until someone invents a copper magnet, we recommend that the ZF S6-40 6-speed transmission oil be changed at 10,000 - 12,000 mile intervals so as to minimize the amount of deposits of the suspended spent synchronizer material from collecting in critical component contact surface areas".

[alwayscode390]

OH, ok ... so that's a recommendation no matter what with our transmissions. Thanks :) ---

[mike100]

is this the AMSOIL some of you have been using?

http://www.amsoil.com/lit/databulletins/g2080.pdf

it does list GM 1052931 on the PDF




Yes.

[efnfast]

is this the AMSOIL some of you have been using?

http://www.amsoil.com/lit/databulletins/g2080.pdf

it does list GM 1052931 on the PDF

http://www.amsoil.com/shopres/products/270px/MTF.jpg

http://www.amsoil.com/shop/by-product/transmission-fluid/manual/manual-synchromesh-transmission-fluid-5w-30/

Yes