I have a 94 TA w/ a trans that was originally from LS-1 Speed. It lasted about 6 mos with my brother. Apparently he was doing neutral drops or something in it. I had a friend of mine rebuild it, and when I put it in, it wouldn't start off in 1st gear unless you put it in low 1. We talked to the guy that built it, only to find that he's had problems with several other 94 4L60's & he actually asked us to call him if we figuerd it out. We ended up just putting a stock valve body in it, removed the vacuum modulator he'd installed, and it worked fine. After a while, it started slipping, so I flushed it, changed the filter, and it was fine. Soon after, a bearing came apart, so we replaced it. It worked ok, even though he softened up the shifts. But it has always had a vibration at 2k RPMs, and when it gets hot, it has a stronger vibration in 2nd gear when you stand on it.... About 2 weeks ago on my way to work, 2nd gear started slipping when it got up to temp and I got on it. A week later, 1st gear started slipping slightly when I stomped on it and it downshifted into 1st. I plan on having my boss help me rebuild it, but I was wondering what I should look for when I tear it down, and what exactly I can do to firm up the shifts.

 

Give frank @ CPT a call, he is the man when it comes to 4l60e's! I am sure he can answer any questions you have. His contact info can be found it the link in my sig.

 

I pulled my tranny today, and with the help of my MVS, rebuilt it and got it back in. Turns out the clip that goes on the inside end of the servo pin broke in half. It ended up mangling the servo a bit. It was too bad to fix, so after a few phone calls, I located a vette servo at AAMCO for $15. I went ahead and put the new frictions, steels, and band in since I had it apart, and adjusted the EPC up a bit. Now it seems to work like a champ.