redbird555

So when I swapped out my clutch a couple months back I took the opportunity to change the trans fluid and went to redline d4. In every t56 I've had this proved to be the best oil, smoother shifting and faster shifting at high rpm. At first everything seemed normal after the change but I wasn't able to really beat on the car due to the crappy MPSS tires it had...seriously, dont know why people like those things...

Fast forward to putting a good DR on the car and I noticed that maybe 1 out of every 4-5 redline shifts going into 2nd would scratch a bit going into gear. First thing I did was verify clutch release which wasn't an issue.

Being that was not a problem I simply chalked it up to me trying to shift too quickly with the new rps clutch and letting out the clutch before it was fully in gear....Then last week I purchased an mgw, always wanted one and figured maybe the shorter throws would help my timing out. Nonetheless the car would still scratch every now and then.

Finally in a last ditch effort I decided to drain the redline out and bought 4 qts of the OEM fluid from the dealer....swapped the fluid out and took it for a drive. It scratched on me 1 time in the very beginning of driving (new fluid probably still working into the blocker rings) . However its been 3 days since then and many hard shifts and it goes into gear great no scratches or protests from the trans. knock on wood it stays that way but it really seems like for whatever reason this trans really didnt like the redline.

Again odd because every t56 I've owned had no issues with it, although it is a synthetic which may cause it to be a tad more slippery than other atf? Trans has 35k on it as well and was babied its whole life so I really couldntsee it having issues with the synchros.

Indepth

Interesting, I've been noticing the same intermittent issue on my T56 after going with Amsoil in my trans. I found this odd because a ton of people have posted both on here and within the Facebook groups with great success with the Amsoil product.

Sounds to me like going back to ACDelco might be the ticket to fixing this...

Millenium Z06

I tried Amsoil in my previous T56 build and notice absolutely no difference using yet vs. Mobil 1 synthetic verses using the stock stuff.
The new T56 build has Royal Purple in it and I don't notice much difference in it either aside from the build of the transmission itself being different.

My understanding is that all T56 is and probably even a 60 60s grind a little bit when cold or mildly warm going into 1st or going into 2nd sometimes. Mine only seem to do it going in the second but my transmission probably has 20 miles on it now

redbird555

redbird555

Indepth

Mine is only on going into 2nd until the transmission is really warm.

Millenium Z06

Mine too

Indepth

Mine only does it intermittently, maybe once or twice until it's warm. How often is your exhibiting these behaviors?

I'm guessing it's only the yellow vettes that have this problem based on our avatars. lol

anth115

Hey guys. I run Redline in the trans of my T56 C6Z and E46 M3. On the BMW forums, someone reached out to Redline to get some more info on this topic and it was recommended to run D4 mixed with MTL in a ~50/50 blend. The D4 is thin enough to cover low temp operations, and the MTL is thick enough to cover the high temp operations. No issues in either car; both see street and circuit time. Nothing wrong with the Delco stuff either but I recall it being a little stiff when cold (I'm in Canada though).
Hope this helps.

redbird555

Millenium Z06

The old trans did it consistently warm or cold, the new build doesn't seem to exhibit it when warm and only negligibly when cold

MTPZ06

I tried many different fluids in my T56 equipped C5Z back in the day (GM, Synchromax, Synchromesh, etc.), and Amsoil Torque-Drive was the best by a mile for shifting cold, warm, high rpms...every scenario was an improvement. Purple stuff was the worst I tried...

Millenium Z06

Not a fan of RP, all swap it out after a few more break in miles. Probably use Amsoil

GOLD72

I have used Redline D4, Amsoil ATF and Amsoil Torque Drive in 3 different corvette Z cars.

Too-Fast

Amsoil Torque Drive here on my 2011 Z07; just changed it in April. I was having some 2nd to 3rd lock out/jamming issues so I changed to the Amsoil and then no more issues. I did practice my shifting and relax a little to allow the shifter to kind of slide into position, so I don't really know if it was the technique, fluid change or a combination of both. All I can say is that switching to the Amsoil did not create any undesirable results and my 2nd to 3rd problem is gone.