Serious transmission issues

[Klutch]

I am trying to help a friend of mine figure out what is wrong with his transmission in his 95 GP. He has taken it to 2 transmission shops and they said it was a electrical problem and they could replace the solenoids to see if it helps but not positive that is the issue. We have already replaced the VSS and the problem is if you are going down the road sometimes it wont shift into overdrive at all but if you put it in neutral and turn it off and back on while driving it will shift right into overdrive and also when you slow down it acts like it dont want to go back to 1st unless you shut it off and restart it or pull the shifter to 1 also randomly the speedometer bounces around or just goes to 0. Anyone seen anything like this before?

[Liquifire]

torque converter issues? hard going into this mode in OD and once he is in it, it stays locked in that mode? If he accelerates into second or third gear and then tries to go into first, does it go or wont it drop down then either?

[minichopper6hp]

I had a 95 grand am with the same tranny, the 4t60e and mine exhibited the condition to where i would come to a stop, but it wouldnt downshift either. It would also randomly neutral while driving, especially while passing someone. I later found out that in those years they had a problem with the valve body machining, one of the valves would wear out prematurely. Im not sure if these are the exact conditions you have, but its a suggestion.

[Trannyman95]

It sounds like shift solenoid 1 may be acting up, but the speedo problem may point to trouble elsewhere. Are there any stored trouble codes? A bad ground connection could also be causing this problem so i would check that out first. The grounds are often all on eyelets that are on the front lower bellhousing bolt/stud so they are pretty easy to check. Do you have access to a scan tool? This will verify if there is a constant speedo signal going to the pcm or if it is just the dash acting up, it will also show what commanded gear the pcm is telling the trans to be in. This problem is going to take some diag time to figure out. You could also look at the wiring harness section that goes to the trans to make sure it isnt pinched or damaged and also make sure the wires going to the vss arent damaged on the back side of the engine or there is an intermittant short to ground

[Klutch]

Thanks for the answers I am going to check the wiring and grounds tonight and report back. Trannyman He was going to take it to autozone to have them pull the codes. As far as the scan tool I have no access to one I did notice today that it will sometimes as if it shifted into neutrual while driving the speedo will drop to 0 and it will rev up but you left off the gas and push it again and it keeps going??