Okay, so I have a 96 Blazer. About a year and a half to two years ago my brother had the transmission rebuilt and then it sat for a while. so I got the truck and drove it around and then the transmission wouldn't shift out of first til 20mph or 3k rpm and I had to take my foot off the gas for it to shift. so we had it rebuilt again and it worked great for about 8 months and then it started slipping REALLY REALLY bad. So we said screw it with the rebuilds and dropped a junkyard trans in there with some 100k miles or so I believe. took it out for a test drive and it wasn't slipping anymore but it wouldn't shift out of first til 20mph or 3k and again I had to take my foot off the gas for it to shift and it would skip second and go right to third. I had no choice but to drive it to school for a couple days so I took it easy (no hard acceleration etc) and just recently the transmission would shift out of first until 30mph or 4200rpm and I had to gun it to get it up that high. but it shifted with my foot still on the pedal. we thought the computer was the problem so we replaced that and it was still doing it, so I'm completely stumped now. I would love any help given. Thank you.

 

im guessing no one has any idea whats wrong with it?

 

Have you tried to locate your symptoms in this thread:
4L60E Information & Common Problems - Compilation

 

i was not aware of that thread... thank you.