I have an 84 Chevy K-20 with a 350 and the factory 3speed automatic transmission. I have problems with it shifting. Sometimes when I start the truck and put it into gear, the transmission will shift and the idle speed drops and then it will occasionally shift out of gear and idle speed increases. Sometimes it will fix itself and go back into drive, but other times you will have to put it into park then back into drive. It also sometimes does this when i am driving or accelerating, shift out of gear like in neutral then go back in. I have been noticing it mostly when warming up. I would like to know what to do about this or if my transmission is just shot? If it is then does anyone know what would be a good replacement?
I would rebulid the 350 transmission that is in the truck now. My bet is that is has never been wirked on. Thay are some of the best that were ever made. You can also get shift kits for this unit to help it shift a little better. Stay with what you have. Frank C ;-)
I have seen this exact problem several times, and every time is was low tranny fluid. Try adding a little at a time, and see if it gets better. I have seen some tranny's that need 1+ quarts more than the stick tells you...I have seen this issue in Chev TH350 and TH400 trannys. -Paul
Take the trans out and remove the pump assy and replace the factory teflon rings with aftermarket steel rings problem solved
