ynot d

when I changed mine this summer the trans oil part # delco 88900333. 4.4 pints

WVZR-1

I don't believe the GM Synchromesh product was ever approved for use in the ZF when the ZF product was discontinued. Many avoided it. I don't believe I've seen a GM statement that contradicts that. Is the current GM product different and approved? Don't have the slightest idea.

Even the Pennzoil product still doesn't mention the use of the product in place of or where GM # 1052931 is specified. This is I believe the latest Pennzoil spec:

http://www.pennzoil.com/wp-content/u...rans-Fluid.pdf

Even Royal Purple who has a "synthetic" Synchromesh product still mentions the use of their HPS or XPR 5W-30 engine oil product as a fill for the GM # 1052931

http://www.royalpurpleconsumer.com/a..._Reference.pdf

Granted lubricants have changed substantially through the years but it might make for an interesting call to the manufacturer of the lubricant you wish to use. I believe that Amsoil does now mention the GM # 1052931 but I haven't looked and I tend to avoid the Amsoil products just because of the "shove" they seem to use to sell the products.

Just sayin'

Richard Raichert

Local in our car club worked at GM and mainly on Vetts for 20 years. He says to stick with GM 5W-30 (GM part no 1052931) syncromesh. I have the origonal owners manual and that is what it calls for also. Do also check the Hyd fluid resevoir. My clutch was engaging at the floor (to low) and I checked the resevoir and it was at add. I added just a little and the clutch now engages at a much higher level.

C4tothefloor

Seems like Amsoil or Penzoil is the preferred choice for the ZF fluid replacement. Does anyone have any experience with one working better over the other specifically to help with syncro issues??

C66 Racing

AMSOIL Synthetic Synchromesh Transmission Fluid (MTF) (Product Code MTFQT)

Hope this isn't taken as trying to "shove" the AMSOIL MTF, but for any that would like to try it, more than happy to get AMSOIL products for forum members at dealer wholesale pricing, about 25% below retail, via the AMSOIL Preferred Customer Program. Drop me a PM if interested.

Tom400CFI

Only a petroleum/chemical engineer could answer this, but I've wondered why a high performing Motorcycle engine oil wouldn't be a good replacement for the OEM recommendation. Why?
*It's engine oil that you can get in the right weight ranges.
*Since motorcycle engines share their oil w/the gearbox, the oil has EP additives in it to manage those conditions.

IDK why I'm posting this...just something that I've wondered about for this trans.

C4tothefloor

Hey guys, so just an update...

I decided to go with the Pennzoil Syncromesh MTF and overall I feel like the shifts are much more smooth. However I'm still getting a slight grind when going from first to second gear. I'm really disappointed but I guess all signs point to trans replacement at this point.

Thanks for all the insight and suggestions though everyone.

mixalive

Before sending your trans for that $2800 rebuild, try the BMW Castrol product as recommended by ZF Doc. Couldn't hurt.. It worked for me with the same symptoms.

Tom400CFI

Boy it's hard to get clarity on this. On the one hand;

THen on the other hand:

mixalive

How much clearer can it be? Try all the cheap solutions before the expensive final solution.

Klondike

If your clutch isn't fully releasing, you are forcing the synchronizers to overcome clutch drag to align the next gear. They can synchronize (align) the gears with a freewheeling clutch disk, but if it's dragging on the flywheel or pressure plate, you're making it work much harder than it is designed to do and it will quickly wear them out. Changing the trans fluid may help temporally but it's not a fix. You need to check the master cyl. level or bleed the slave cyl. to get all the air out of the system.

C4tothefloor

Have you found a preferred bleed method and is there anyway to tell when it is fully bled?? I have actually replaced my clutch master and slave as they were original to the car and I've been told fail over time. My understanding is that it's a sort of "self-bleed" system as far is if you don't have any bubbles in the fluid and the pedal is not spongy then you are fully bled...is this not correct? The part that does not make sense to me is why is this happening in only 2nd gear and not all of them??

Tom400CFI

If your pedal is not spongy, that is pretty strong evidence that it's properly bled.

If you only grind in 1 gear, (2nd gear, in your case) that is pretty strong evidence that there is an issue w/the synchro for just that one gear.

IIWM, I'd try a few different oils (cheap) and see if one makes it drive acceptably...then I'd drive it as long as I could and prepare ($$$) for a rebuild in the near future.

mike100

You can change the trans oil and make sure the clutch hydraulics are in proper operating condition- if it still grinds, you need hard parts internally I'm afraid.

whalepirot

Which is a major reason the ZFs fail. The synchros are also the weak part of the ZFs,

mike100

I wouldn't waste another $50 in oil just to find out what the OP already knows. It shouldn't grind with any fresh trans oil.

5abivt

In my opinion.. The FIRST step should be to bleed that slave and get new fluid in there. Reverse bleed from the Slave it's very easy and much cheaper than changing the trans fluid.

Bill built up a brand new blue tag zf I bought when gm dumped inventory. It's for my 93 which I had an 8000rpm 388 stroker in. It has castrol 10w60 and the fluid came out clear. That car has a McLeod street twin and McLeod master and it was reverse bled.