Are there alternatives to the GM-specified 5W30 transmission fluid, part number 1052931, for the ZF manual transmission? I've seen somewhere that the trans maker recommends only that or synthetic motor oil Castrol RS 10W60. I've also seen a posting saying that a CorvetteFever article recommended Mobil 1 10W30 motor oil. Yes - I know it's usually best to stick to manufacturer's recommendations, but my hard shifits at cold startup (it's a '94 with only 25K miles) tell me I probably need new, and maybe improved, fluid in the trans case. I can't find the Castrol, or I'd already have put that in. Are there any synthetic, workable, alternatives that anyone's heard about?
Thanks!

 

I have the ZF 6-speed and put in Valvoline Synpower 5W-30 motor oil. I hadn't heard that you should run any thicker than that. Synthetic oil should be synthetic oil wether it's GM specified for the trans or engine oil. I put mine in this spring and have put about 4K on it including autocrossing and it works great.

 

Try the redline 10W60 I think you will be plesantly supprized with the improvement in shifting and lubracation.

 

Engine oil does not belong in this trans, IMO. If you have ever put in GM 1052931 you can smell the additives in this GL-3 gear oil that is rated at 5W-30 (beware - gear oil ratings are different than motor oil ratings and the numbers overlap). The 60W oil with the right additives makes more sense - that is close to 5W-30 in an motor oil rating, but somebody said they tried it and it made the ZF notchy.

If somebody can come up with a GL-3 gear oil for the ZF I would be more than happy to give it consideration for my $4,000 transmission. Otherwise you are participating in the "big experiment" and please don't sell me your car.

Use the 1052931 and don't let anyone tell you this was ever used as a motor oil, no way with the additive package. Tastes good too. Snap on sells the socket to get the plugs out, sorry I can't remember the size of the allen - but is something like 17mm.

Flush with 1052931 was night and day with my ZF and I recommend it. The guys that race recommend flushing with this oil every year or so. I have better things to do than have to spend $4,000 rebuilding a perfectly good trans because some parts jocky see's 5W-30 on a bottle and invents a story that it is engine oil. It's NOT engine oils

There, I feel better - but it's your choice. Good Luck with it.

Pete

 

Thanks for taking the time for a thoughtful response. I'm taking your advice and going with the GM fluid for my "94 ZF transmission.
Thanks Again!
David Dufurrena