Synthetic Z06 Manual Transmission Lube??

[hzl6cm]

Since my the tranny on my '04 Z06 is pretty notchy when cold I plan to convert to a synthetic transmission lube but wondering which one I should use and what experiences other people have had. I've used Redline MTL successfully on several cars in the past, including the 4-speed on my '70 Stingray. However later model GM manual trannys take Dextron III ATF - I didn't know if Redline synthetic ATF would work in a manual tranny or if something else would need to be used. A few years ago, when I had a similar problem with my '01 Camaro SS somebody on the F-body forums stated that the T56 was filled with synthetic fluid. However, I don't think that is correct since the sticker on the side of the tranny and the owners manual just say to use Dextron III ATF and don't say anything about a synthetic fluid. I've searched the forums and site and couldn't come up with any info on this issue. I've posted in the C5 section instead of just the Z06 since this issue would be applicable to any C5s. Thanks.

Kevin

[ErnieN85]

Kevin, I had this discussion with the tremac engineers at Carlisle last year. Officially The recomendation is ATF dexron specifically. Gm says any dexron is ok for warranty, The Redline D4atf is one of the better ones. and the engineer i talked to said it should be better however they haven't done any specific tests.

That said I changed mine to Redline and seemed to have a smoother shift. However when it's cold it's still a bit stiff. I was told that Amsoil ATF works better in real cold weather.
(haven't tried it though)

[c4c5specialist]

Redline D4ATF is what should be used in the T56, in the Redline product line.
It will help your condition.
Allthebest, c4c5

[hzl6cm]

Thanks for the replies - I knew that I could count on the list for the information that I needed. The synthetic ATF should help also if the transmission heats up during track days since it will remain stable at a lot higher temperatures than the normal ATF does - that is the reason I went to synthetic ATF in my half ton suburban last summer after we bought a 29 foot travel trailer. I feal better with the extra heat protection in the Vette since GM didn't see fit to install a transmission temperature guage in the car.

Kevin

[66427-450]

I'll second the Redline D4 ATF, pick up 4 quarts to be sure, but it'll only take a touch over 3........ fill till it comes out of fill hole.

[c4c5specialist]

HI there,
Standard Dexron 3 is good to 275F.
Allthebest, c4c5