GREGGPENN

I searched the web and found the contact @ ZF for information about lubes on our S6-40 manual transmissions.

So far, he has recommended the GM lube, the Castrol 10w-60 (thru BMW) and provided a list of ATF fluids you can use. He reports that selection of gear lubes from and API class (ie. 1-5) are not recommended. In other words, you cannot globally classify the proper lube as a class 3 -- AS POSTED IN THE TECH TIPS!!!!!!!!! This information is incorrect.

The reason is the sinter-makeup of the phosphor-bronze synchros. (Sinter refers to the heating of powder/granular forms of metals in order to form solid products). For the S6-40 synchros, the manufacturing result is a porous metal synchro -- in which the lube actually penetrates the synchro. If you use a non-approved lubricant, this "porosity" can be compromised, affecting wear/shifting.

I sent ZF's contact an additional email questioning the excessive wear (17%/15K miles) as reported by Bill @ ZFDoc.com. I'd like him to comment on those findings. And, because the 5-speed version of ZF's transmissions (used in Ford trucks) uses ATF fluid, I wanted him to comment on the GM vs. Castrol vs. ATF pros/cons.

I concluded (my email to the ZF contact) by proposing 20 years of lube engineering should update offerings of lubes for our transmissions. And, I wonder if/how companies like Redline/AMSOIL could provide alternative choices for the ZF6 -- if they weren't approved by ZF.

Until I get a response, here is the link to the ZF list of lubricants (TE-ML 02). Approved ATF lubricants according to the ZF lubricant class 02F are mentioned on page 12.

http://www.zf-transmissions.com/TE-ML002.pdf

Again, the allowable choices are GM 1052391, Castrol TWS 10w-60, and the ATF's listed in the document link above.

BTW: Recommended change intervals are 30k-40k miles according to ZF.

GREGGPENN

At the very least, I thought AMSOIL, Redline, and/or other reps would chime in....

rocco16

Gregg, I couldn't find any information in the link that did me any good.
Maybe I'm dense.....

Can you decipher it for me??

Larry
code5coupe

___________
I ain't easily impressed....

Rocket22

When shoul I change the man. trans oil? I just bought it and have driven 3k miles, now at 125K.

rocco16

Tomorrow.

Saturday at the very latest.


Larry
code5coupe

__________
I ain't easily impressed....

AORoads

Agreed!

bogus

www.c4guru.com - Changing ZF6 Fluid

GREGGPENN

I interpret it as being a list of ZF's class 02 lubes. This does not correspond to API classes (don't know if it has an equivalent). Only the ATFs listed are considered optional to the GM/Castrol (warranty coverage). BTW: the real meat of the document is the list of lubes in the 2nd half....

I note that most lubes (on the list) are foreign-made and/or not available in the USA (at least not easily). Since ZF is in Germany, I'm not surprised. But, there are a couple of things I got out of the first exchange with the ZF lube rep.

The ZF S6-40 phosphorus-bronze synchros are porous. And, if the lube is intended to penetrate them, I vote for the thinner GM fluid vs. the 10w-60 Castrol. With Bill's evidence of wear -- despite Bill's (ZFDoc's) apparent endorsement, with my experience that it's stiffer, with a caution about using too think a lube in cooler temps, and with the knowledge that the synchos are porous, I see evidence pointing to the use of thinner lubes.

Obviously, the trans has some high shearing forces and because of their caution about standard API class lubes, the lube selection seems limited -- until you read the list of ATFs you can use. Hmmmmm.

A friend has a 5-speed ZF in his Ford 7.3 diesel. It calls for Mercon synthetic ATF. And, it sees higher stress than our vettes. Mercon ATF is on the list and my friend has 300K on his truck (though the tranny just had to be replaced). Til then, and even now, he thinks it was a good lube. Because thinner lubes would seem good for porous synchros, I'm thinking an ATF might be worth a try -- to see what function is like.

The GM fluid does not look like an ATF. But, Ford dumps it in their ZF-equipped trucks. Does that mean there's a real difference in the trannies? With respect to the synchro's, I doubt it. So, why the diff? I bet it has nothing to do with the "right" choice. And, I'm wondering if ATFs are a better choice as alternatives -- than the GM stuff -- especially synchetic ATFs.

gp

CentralCoaster

Their long list of literature does not specify class 02F for the ZF S6-40 transmission. It's not on any of their lists.
That spec is useless anyways, there's one or two small-time Bubba ATFs, and the rest are not available in the U.S. 99.9% of these transmissions were put in Corvettes and sold in the U.S, so to have a list of lubes made in 3rd world country doesn't make a lick of sense.

This U.S. rep seems like he's making stuff up as he goes along.

ittlfly

I talked with Bill awhile aback and he was still "OKing" BMW Redline. I hope he is still of the same opinion. These things are a bit expensive to work on.

GREGGPENN

I did not have a place to host the pdf originally sent by the ZF rep. Since you don't believe what I said, here's a jpg of it. And, this is the info relayed by Bill. He's not making it up. If anything, ZF sucks. They (ZF) have not replied to my "harder" questions about Bill's findings on wear of the Castrol and why better lists aren't available for the US (and newer, updated lubes).



There's no such thing as "BMW Redline". You probably meant BMW Castrol.

CentralCoaster

I don't doubt that he said that. I just think he's full of it. It doesn't make any sense, and it disagrees with their own literature.

ittlfly

Your right. I meant to say, Redline MTL SAE 70W 80

GIJoe

Make sure you make note that new part number for the GM oil is: 12345349

I found this out the last time I went to get some. They were still able to find it with the old number, but many parts places may not be able to cross reference this anymore.

I had the FAQ updated to reflect this. Might be something you can pass along to ZF as well the next time you reply to them.

GREGGPENN

You don't doubt who said what? Who's full of it? Bill? He's the middle man here...

Which literature is in disagreement? ZFs and GMs?

corvetteronw

I'm doing this to mine tomorrow. I used the 12345349 part number at the local Pontiac dealer. $13.75/quart! I guess she likes the good stuff!

CentralCoaster

pdf from ZF rep disagrees with ZF website and doesn't corroborate with ZF lube specifications.

ZF's change interval doesn't agree with GM's

Performance of ZF's recommended Castrol is questionable IMO based on Bill B's test results, albeit there is nothing to compare with.

Bill B recommends Castrol over GM fluid despite those test results and despite driveability comparisons by many forum members that favor GM.



Somebody is clearly wrong, but the only ones who have any stake in the matter are us, the owners.

CentralCoaster

Holy cow that's expensive.

Somebody said Pennzoil makes the GM stuff. They also make this:



http://www.pzlqs.com/Tech/Pdsheet/Do...omeshFluid.PDF

PENNZOIL®SYNCHROMESH FLUID

PRODUCT DESCRIPTION

PENNZOIL®SYNCHROMESH FLUID is a synchromesh transmission fluid designed for certain manual transaxles and manual transmissions used by General Motors or Chrysler. PENNZOIL®SYNCHROMESH FLUID is formulated with high quality paraffinic base stocks, a fluidity modifier, multifunctional performance additives, corrosion inhibitors, a foam suppressor and a shear stable viscosity index improver additive. It provides excellent oxidation stability, low temperature performance, excellent synchronizer performance and compatibility with yellow metals, such as bronze, brass and copper components found in manual transaxles and transmissions. This product will satisfactorily lubricate General Motors or Chrysler manual transaxles and transmissions from -40°C to +150°C.

APPLICATION

PENNZOIL®SYNCHROMESH FLUID is specifically formulated for synchromesh transmissions used by General Motors requiring General Motors Part No. 12345349 (Specification No. 9985648) Synchromesh Transmission Fluid or Chrysler transmissions requiring Part No. 4874464 (Specification MS-9224). It is also recommended for use in General Motor transmissions requiring General Motors Part No. 12345577. It is listed in the Pennzoil Lubrication Recommendation And Capacities Guide as “GLS.” PENNZOIL®SYNCHROMESH FLUID is NOT intended for all GLS applications. You must verify the manufacturer’s part number, indicated by a superscript number and found at the end of the vehicle application listing.

BENEFITS

•Exhibits excellent low temperature performance
•Meets GM Specification 9985648
•Suitable for use in GM manual transaxles and transmissions requiring GM Part No. 12345349 or 12345577
•Meets Chrysler specification MS-9224
•Suitable for use in Chrylser transaxles and transmissions requiring Part No. 4874464
•Excellent synchronizer performance
•Excellent yellow metal compatibility


Also:

"A post on the message board at www.oilanalysis.com found Synchromesh to consist of a 5W30 non-detergent oil with a friction modifer and an EP (extreme pressure) additive. It is made under contract for General Motors by Pennzoil (APC 3378) or by Texaco (Code 1874 MTX Fluid).

Pennzoil Synchromesh Fluid can be purchased as that brand or as the equivalent products: Quaker State Synchromesh (Quaker State is part of Pennzoil), Texaco Synchromesh, GM Synchromesh, or AC Delco Synchromesh (part number 89021808). GM Synchromesh retails for about $10 per quart bottle at GM dealerships. Pennzoil Synchromesh is sold at many Auto Zone auto parts stores for about $5 per quart and should be available from Pennzoil distributors. Texaco Express Lube stores use Synchromesh but the stores I contacted would not sell the product by itself to customers. Pennzoil Synchromesh can be purchased in 5-gallon containers from oil-store.com. "

CentralCoaster

Some internet searching says GL-5 fluid (not GLS) will eat the synchros...

And that GM synchromesh is highly regarded by Honda S2000 and Acura owners in their 6-speeds which call for very similar oils to the ZF6.

GREGGPENN

I completely understand your point about Bill's endorsement of the Castrol vs. his own wear tests. Regarding the forum and preferability, I've never seen a clear preference for either though. When I've posed the question of preference, as many people agree as disagree with my observation that the GM fluid shifts better. I attribute this to the thicker viscosity. (ZF documentation clearly states too thick of oil will compromise "shiftability" in colder temps. I simply begin to feel it at temps higher than noted. The Castrol is thicker than the GM stuff).

I haven't seen a contradiction between the ZF rep's documents and their website. What is it you're refering to?

Also: Thanks for the heads up on the Pennzoil. As with Redline/AMSOIL products that claim direct replacement for the GM fluid, I have to wonder how the determination was made -- and why ZF wouldn't add the new products to their "list". (Especially if the product is made under contract?)

gp