ZF 6 oil

[secondchance]

I know this subject has been beat to death. One simple question - what was the factory fill? Any particular reason we debate between Castrol and Redline? I must have missed something.

[ZR1Vette]

Was the ZF tranny made in Germany by ZF Getriebe GmbH in Saarbruken, Germany? Or did ZF have a manufacturing facility in the US (as it does now)?


If the answer to the first question is 'yes' then probably the "factory fill" would have been Castrol 10W-60

[secondchance]

I am not too crazy about changing fluids every year (10 - 12,000 miles) if I can avoid it.
I have 110,000 miles and perhaps changed it once at around 40,000 miles or so with no issue.
Am I taking too much risk? I was thinking if I stayed w/ factory fill, perhaps I could avoid anual change.

Your thoughts, guys?

[Dynomite]

Originally Posted by secondchance

I am not too crazy about changing fluids every year (10 - 12,000 miles) if I can avoid it.
I have 110,000 miles and perhaps changed it once at around 40,000 miles or so with no issue.
Am I taking too much risk? I was thinking if I stayed w/ factory fill, perhaps I could avoid anual change.

Your thoughts, guys?

I think you are with majority

I prolly change transmission and differential oil every 50,000 miles on some vehicles....longer change interval on most vehicles.

But then again...the Z gets special treatment......and I will prolly change transmission and differential oil every 15,000 miles more or less on the Z. I did add the drain plug in the differential to make changing oil a lot easier on the 91' Z

I use castrol TWS 10W-60 (transmission), Mobile 1 75W-90 (Differential) and Amsoil 10W-40 (Engine).

[secondchance]

I guess I will stay with factory fill.
10-12000 miles change for BMW Castrol comment concerns me.

[Dynomite]

Originally Posted by secondchance

I guess I will stay with factory fill.
10-12000 miles change for BMW Castrol comment concerns me.

I think the issue of suspended spent synchronizer material is associated with any transmission oil you might use (more so with GL-5 than GL-4 lubricants because of the additives - see below)

Not necessarily associated only with (I think even less associated with - see below) the use of Castrol TWS 10W-60

The recommended oil change interval of 12,000 miles by Bill B. will reduce the accumulation of that suspension of synchronizer material which may be more significant an issue with the ZF S6-40 6-speed transmission.

Some bits of additional information by others

"Some late model Corvette transmissions (ZF) have a reputation for generating significant quantities of bronze particulate mud and require both special synthetic lubricant and frequent changes to achieve old age. At one point a few years ago I think there was just one lube in the world (maybe by Castrol) that was ZF approved."

"API GL-4 and API GL-5 products typically use the same extreme pressure (EP) additive system, with the API GL-5 having about twice the concentration of EP additive as API GL-4. In service, these additives become active under extreme load and temperature when the protective oil film can be squeezed away. EP additives work by forming wear-resistant compounds with the metal of the gear tooth surface. As the gears mesh, these compounds shield the gear teeth from direct metal-to-metal contact that would cause wear and damage to the gears. If too little of the active additive is present, proper protection would be compromised. Too much of this EP additive could cause excessive chemical corrosion of the gear surface.

If an API GL-5 gear oil is used in a application where API GL-4 gear oil is called for, chemical corrosion of "yellow metal" components may occur, such as bronze synchronizers, brass bushings, etc. This may lead to shifting difficulties or shortened equipment life."

[Hammer]

Originally Posted by Dynomite

I think you are with majority

I prolly change transmission and differential oil every 50,000 miles on some vehicles....longer change interval on most vehicles.

But then again...the Z gets special treatment......and I will prolly change transmission and differential oil every 15,000 miles more or less on the Z. I did add the drain plug in the differential to make changing oil a lot easier on the 91' Z

I use castrol TWS 10W-60 (transmission), Mobile 1 75W-90 (Differential) and Amsoil 10W-40 (Engine).

Did you have to use any of the posi additive with the Mobil 1?

[Dynomite]

Originally Posted by Hammer

Did you have to use any of the posi additive with the Mobil 1?

No...you said I did not have to with Mobile 1 75W-90

Actually I have installed Mobile 1 75W-90 in the differential but have not driven the Z. On the Mobile 1 75W-90 it says limited slip applications right on the bottle. Kind of matches the tag on my differential fill plug (Use limited slip oil only....or something like that)

If I have to go with a slippery additive, let me know
I know.....you are now concerned with going to BG on that long trip with new 410 gears and experimental Mobile 1 75W-90

[tomtom72]

Originally Posted by secondchance

I am not too crazy about changing fluids every year (10 - 12,000 miles) if I can avoid it.
I have 110,000 miles and perhaps changed it once at around 40,000 miles or so with no issue.
Am I taking too much risk? I was thinking if I stayed w/ factory fill, perhaps I could avoid anual change.

Your thoughts, guys?

The only thoughts that I have are: what's the big deal on changing the trans fluid every two yrs or so, or even every year? The original fill is NLA from GM. The new P/N is probably not the same as the OE/BG fill as when the C4 was in production, no? That makes sense to me. The C5 & C6 box and for that matter most of the other manual gear boxes that GM uses now use the same stuff. You guys have lifts & a place(s) to work! Try doing this stuff in a parking lot or in the middle of the night so you don't loose your rented space, or worse yet trusting your prized possession to some non-caring tech!

Also, I remember reading somewhere that GL numbers are not substitutable in that if you need GL3 a GL4 fluid will not cover your needs. I think I saw that on Bill's site. I also remember seeing on his site that the zf was spec'ed at an odd ball GL number not commonly used here. I want to say GL3(?) but I don't remember now, sorry. Oh, it's the same with the gear fluid that GM sells, it's not exactly what came with our cars from BG either. It's for the 5's & 6's set up.

Lastly, when I looked at that wear test/fluid lubrication degradation test over at Bill's site I was kind of amazed at the rate of fall off of viscosity. Now I'm not a Petro/chem Engineer but the fall off was alarming to me. Take those results and add them to the issue of the synchronizer collar getting gummed up with the sludge causing bad things to happen, eventually...I might add that this is probably the weakest argument for frequent changes...you wind up at Bill's shop for a rebuild which costs a few thousand dollars.

I know it's a PIA, but then if you do the schedule so that once the car is up on stands, or a lift, you do all the fluids at once. This way you're not doing them at any number of separate sessions, which to me is a PIA! I used to do all my "under car" work at the same session: motor oil, trans oil, gear oil, fuel filter, clutch fluid & brake fluid bleed thru's, coolant + stat change. The last three fluids were once every two yrs, to lighten the work load.

To me it's a question of having a schedule & sticking to it. Also, and this is a bit half-assed, I like to think that once my maintenance session is over, I'm go to go for the rest of the year except for oil changes.

Sorry for what looks like a rant Yun. It's just that I'm old school, or maybe just old & senile, but machines need maintenance.


Tom

[secondchance]

Originally Posted by tomtom72

The only thoughts that I have are: what's the big deal on changing the trans fluid every two yrs or so, or even every year? The original fill is NLA from GM. The new P/N is probably not the same as the OE/BG fill as when the C4 was in production, no? That makes sense to me. The C5 & C6 box and for that matter most of the other manual gear boxes that GM uses now use the same stuff. You guys have lifts & a place(s) to work! Try doing this stuff in a parking lot or in the middle of the night so you don't loose your rented space, or worse yet trusting your prized possession to some non-caring tech!

Also, I remember reading somewhere that GL numbers are not substitutable in that if you need GL3 a GL4 fluid will not cover your needs. I think I saw that on Bill's site. I also remember seeing on his site that the zf was spec'ed at an odd ball GL number not commonly used here. I want to say GL3(?) but I don't remember now, sorry. Oh, it's the same with the gear fluid that GM sells, it's not exactly what came with our cars from BG either. It's for the 5's & 6's set up.

Lastly, when I looked at that wear test/fluid lubrication degradation test over at Bill's site I was kind of amazed at the rate of fall off of viscosity. Now I'm not a Petro/chem Engineer but the fall off was alarming to me. Take those results and add them to the issue of the synchronizer collar getting gummed up with the sludge causing bad things to happen, eventually...I might add that this is probably the weakest argument for frequent changes...you wind up at Bill's shop for a rebuild which costs a few thousand dollars.

I know it's a PIA, but then if you do the schedule so that once the car is up on stands, or a lift, you do all the fluids at once. This way you're not doing them at any number of separate sessions, which to me is a PIA! I used to do all my "under car" work at the same session: motor oil, trans oil, gear oil, fuel filter, clutch fluid & brake fluid bleed thru's, coolant + stat change. The last three fluids were once every two yrs, to lighten the work load.

To me it's a question of having a schedule & sticking to it. Also, and this is a bit half-assed, I like to think that once my maintenance session is over, I'm go to go for the rest of the year except for oil changes.

Sorry for what looks like a rant Yun. It's just that I'm old school, or maybe just old & senile, but machines need maintenance.


Tom

I hear ya, Tom. I think I have a solution - drain the old fluid, run it through a coffe filter and the refill - JUST KIDDING!
I guess I am stuck with an additional annual fluid change. Knowing my personality, once I hear these things it tends to make me lose sleep until done the way it suppose to be.
Thanks guys for all the info.