Castrol 10W-60 TWS

[Hib Halverson]

Originally Posted by tf95ZR1

(snip)

I'm gonna be in for a bit more work: with my lowered car,
my drain plug is ground flat.(snip)

Your car is lowered so much the drain plug in your ZF is ground flat?!
Wow.

With virtually no suspension travel the car must be a handful sometimes, but darn, I'll bet it looks really cool.

[tf95ZR1]

I don't want to hijack this thread, and maybe I exaggerated a bit
about being ground flat, but a hex will definitely not work as is.
It used to hit on speed bumps (not anymore!) and still handles just
fine, even at HIGH speeds.

[Dynomite]

Originally Posted by Hib Halverson

Your car is lowered so much the drain plug in your ZF is ground flat?!
Wow. With virtually no suspension travel the car must be a handful sometimes, but darn, I'll bet it looks really cool.

One other possibility is the transmission is tilted down a bit more than normal caused by loosening of the C-Beam/Transmission Bolts. Maybe time for ZFdoc C-Beam Plates installation

C-Beam Normal alignment is 1.77 in from top of C-Beam to the under body at the location of the front Universal Joint Bearing.
Side to side alignment is 1.1 in from C-Beam Side wall to passenger side under body side wall at the same location.
I raise the transmission just a bit more than the 1.77 in criteria (say 1.5 in clearance) to account for weight (engine and transmission) once the transmission is released from the jack support.

Originally Posted by Hib Halverson

Before Castrol changed the marketing of the 10W60, it was popular, I guess, because it was approved by BMW. I've been skeptical because of a conversation I had a number of years ago with Bill Boudreau who told me that, according to his testing, the oil didn't last very long and needed to be changed every 10,000 miles.

I thought Bill Boudreau was referring to the spent synchronizer material (which would accumulate in any oil) and not to some deterioration of the Castrol 10W-60 oil

"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".

[Dynomite]

Just had to revive this 2015 Discussion for those that missed it first time around

Originally Posted by Hib Halverson

Red Line does not make a product called "Heavy Shockproof full synthetic 75W90."

It makes a product called "Heavy Shockproof" but that's not suggested to be used as a transmission lubricant. Red Line also makes "MT90" a 75W90 GL4 gear lubricant intended for old-fashioned manuals such as Muncies and Warner T10s and it makes a 75W90 GL5 for rear axles.

Regardless of what Marc may say, neither of the above products is suitable for use in a ZF S6-40.

The Red Line products which are suitable for a ZF are:

MTL, which is a GL4, 75W80 and is the most commonly recommended Red Line synthetic product for ZF S6-40s.

Light Shockproof, which is suggested for use in ZFs subjected to severe duty.

I stuck with Red Line Light Shockproof because 1) the shift feel and 2) that I can go 36,000 miles between changes.

Hib.........Very Interesting in regard to Red Line MT90.......The most recommended Oil for the Toyota Tacoma V6 manual Transmission is Red Line "MT90" a 75W90 GL4 (MT90 from Summit Racing ). The Toyota Discussions suggest GL5 are too slippery for the Syncros of the Toyota Manual Transmissions. And yes.....many of the guys use Red Line 75W90 GL5 in their Differentials. I use Mobile 1 75W90 in all my Differentials.

I do use Castrol 10W-60 in ALL Corvettes ZF S6-40 Transmissions.

[XfireZ51]

BMW dropped the Castrol TWS several years ago in favor of their own branded oil. Since then I have been using the Amsoil Manual Synchro Oil and find it to shift a bit smoother with no other issues. Marc H uses that oil for the ZF.

[Dynomite]

Originally Posted by XfireZ51

BMW dropped the Castrol TWS several years ago in favor of their own branded oil. Since then I have been using the Amsoil Manual Synchro Oil and find it to shift a bit smoother with no other issues. Marc H uses that oil for the ZF.

Do you have a picture of a quart of Amsoil Manual Synchro Oil ?
Is that Amsoil Manual Sunchro oil 75W-90 weight?

Ebay has all kinds of Castrol 10W-60 for sale (Edge and TWS) which is what I have in all ZF S6-40 Transmissions including a Black Label recently rebuilt by Bill Boudreau and a New Blue Label ZF-S6-40 Transmission

Marc Haibeck now as of 2016 suggests Castrol TWS and Castrol Edge (both 10W-60) as alternate ZF S6-40 Lubricants and is now using Amsoil MTF synthetic 5W-30 manual transmission specialty lubricant. Red Line MTL is also good. For an application that uses a single mass flywheel, Marc has found that Red Line Shock Proof Heavy is the best for suppressing gear rattle.

Bill Boudreau now suggests The ZF S6-40 6-speed transmission is lubricated by engine type oil. Manufacturer recommendations specify the use of GM P/N 1052931 (5w-30) or BMW P/N 07510009420 (10w-60) oil. Bill also suggests more Frequent transmission oil changes will ensure lower Pb particle levels (the porous Phosphorus-bronze (Pb) material of each synchronizer) suspended in the oil.

[jss06c6]

Just got my ZF back from Bill. I'm running BMW M-turbo 10w-60. 100 miles of Twisties this morning with a lot of up & down shifts. Never skipped a beat. Smooth shifts without exception.

Sent from my XT1585 using ZR-1 Net Registry mobile app

[9T1 Red ZR1]

Hi,
I ordered the Castrol TWS but they shipped Castrol Edge Supercar 10W-60. Is this the same or should I return it?

Thanks,
Bill

[jss06c6]

Not sure.. try to get the oil specs and constituents, zinc, etc.. compare to the BMW M-turbo 10W - 60.

Sent from my XT1585 using ZR-1 Net Registry mobile app

[Matt B]

I just went though this threat as in our German forum we currently have a case of transmission failure and at the same time I'm tidying up my new Z.

My car, as mentioned before, is a 18.5kmls example and I strongly assume (but don't know for sure) that transmission fluid is still factory filled. There are two particular concerns in my case:
- avoid that the new oil removes old debris too aggressively leading to bulky particles that may clog oil passages
- make sure the thing will survive German Autobahn speed.

Castrol Edge 10W60 is fairly easy to get here, but as Marc Haibeck recommends Amsoil 5W30 I wonder which will work better or safer. Marc's recommendation seems much thinner and therefore sounds like improved lubrication at all temperatures.
I don't think either is wrong but is there any better or worse?