ZF6 Question/Help
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
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'
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'
Racer
Joined: May 2013
Posts: 405
Likes: 15
From: Panama City Beach Florida
94 6 sp
This seems to be a heavily debated topic. I am currently running Amsoil Synchromesh. I am not very happy with the product. It works fine in the cold weather. But in the warm weather, it works fine until the fluids get hot. Then I get grinding going from first to second. I am checking this post to see if there are any updates on recommendations. I did a search on Rockland Standard Gear and they recommend GM 1062931 and Castrol RS only. It looks like the ZF Doc is being vague on recommendations at the moment.
Dizwiz.. What GM part number Synchromesh are you using?
Dizwiz.. What GM part number Synchromesh are you using?
Premium Supporting Vendor
Joined: Aug 2001
Posts: 5,364
Likes: 38
From: King George VA
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.
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.
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AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
C66 Racing #66 NASA ST2, SCCA T2
AMSOIL Dealer (Forum Vendor)
AMSOIL Preferred Customer Program (Members buy at Wholesale - a savings of about 25%)
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
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.
*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.
Thread Starter
Advanced
Joined: May 2012
Posts: 51
Likes: 0
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.
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.
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Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
Boy it's hard to get clarity on this. On the one hand;
THen on the other hand:
In my case, it was using the bmw 10w-60 crap instead of the fluid that the factory says should be in there.
When i went to change that crap out, there was all kinds of bronze glitter in my fluid. (when changing the correct fluid out, the old fluid is virtually clear)
The solution was simply replace the bmw castrol 10w_60 crap with gm syncromesh which is what gm recommends for zf6.
Once i did this, the grinded shifts went away.
When i went to change that crap out, there was all kinds of bronze glitter in my fluid. (when changing the correct fluid out, the old fluid is virtually clear)
The solution was simply replace the bmw castrol 10w_60 crap with gm syncromesh which is what gm recommends for zf6.
Once i did this, the grinded shifts went away.
THen on the other hand:
Team Owner
Joined: Feb 2006
Posts: 23,218
Likes: 117
From: San Antonio Texas
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.
Last edited by Klondike; Oct 28, 2014 at 02:43 PM. Reason: clairification
Thread Starter
Advanced
Joined: May 2012
Posts: 51
Likes: 0
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.
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
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 ($$$) for a rebuild in the near future.
If you only grind in 1 gear, (2nd gear, in your case) that is pretty strong evidence that there is an issue w/the synchro for just that one gear.
IIWM, I'd try a few different oils (cheap) and see if one makes it drive acceptably...then I'd drive it as long as I could and prepare ($$$) for a rebuild in the near future.
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
Safety Car
Joined: Aug 2008
Posts: 4,344
Likes: 48
From: San Marcos CA
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.
Safety Car
Joined: May 2002
Posts: 4,659
Likes: 82
From: Toronto ontario
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.
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.