Had my tranny rebuilt a couple months ago. Although I told the shop to use GL-4, who know what they used. It' s been a little over 3k miles since the rebiuld and shifting has gotten quite notchy lately. It's been difficult to get into 1st and reverse sometimes. Second was rough as well.

Orderd the Redline from summit racing and swaped out the fluids today. So far shifting is much better. Have not encounterd any problems with 1st or reverse and second is noticeably smoother. I have only made a few short trips with the car so time will tell if this solves the problem, but so far I am pleased with the synthetic fluid.

Just thought I would share my expierence.

 

They probably used cheap Unocal 80/90 weight fluid. Just a guess. Glad Redline helped.

 

Is it really just a guess? Do you know what they use at certified?

 

Yes. Checked with Tom and his tech after my install. Blackstone report coming back on mine in a few weeks for insurance. Just happened to be over there yesterday getting my old unit off of their shelves.

 

You are required to share those results.

 

40 miles of city driving with the new fluid this morning. Things are much better. Never had a problem in 1st, and reverse only resisted me once but that has happend every so often all my previous manual trannies.

All around better shifting. I think I also need to adjust my clutch pedal to engage a bit lower. Since the new clutch was put in it grabs at the very very top, which I don't really car for. I can't expain why I think it will make shifting better or can't back it up with techinical facts, but it seems it be causing some engagement issues since it grabs so high. We'll see if it does anything.