91 grand prix trans problem

i have a 91 grand prix. wont shift from 2nd drive or drive to over drive. ive tried shifting manuelly still doesnt work . i changed fluid and filter. rechecked trany fluid level its ok. there wasnt any metal shavings or anything in the pan. the old fluid was kinda dark pinkish color didnt smeel burnt. ive checked out the tcc solenoid it checks good
checked for codes. showing no codes at all . checked the vacum hose and the modulator . it all checked good. can someone pls help me.

I dont really understand? You say it wont shift from 2nd and then you say it wont shift from drive to overdrive. Which is it? When you manually start in 1st, will it start moving? then manually move it to 2nd what happens? Then manually into drive, what happens now?

you can check to make sure that the vacuum modulator valve vacuum hose is hooked up and also check and make sure the throttle boost cable isnt broken, but if booth look fine, the tranny sounds like its time for a rebuild.

ok its like this . i start out in low (1) it takes off like its suppose to .shift to 2nd shifts fine then shift to drive itll speed up to around 50 mph and shifts to drive but nothing happens the motor just revs . ive already checked the vacum hose and modulator they are fine . could it possibly be one of the shift solenoids or maybe the speed sensor?? how do u check the selenoids?? ohm them ?? if so which connections do i use to do so ? i thnk o the wire conector there are letters a,b,d,and e

In a 1991 you have a 4t60 not 4t60e. The shifts are completly controlled by fluid based upon governer pressure and throttle pressure. Have you checked the fluid level?

yes ive checked the fluid and it is ok in fact checked it 3 different times still ok . u were saying mine is operated by fluid presure only then why does it have a 1-2 shift solenoid and a 3-4 shift solenoid? could maybe the speed sensor have something to do with the shifting also??

it does? I could be wrong. let me check.....

Alright then, I guess they started the 4t60e a little earlier than what i thought. I apologize. I also found this... If that may help out. I couldnt find any resistance values for the solonoids, but i do know where you can find a lot of troubleshooting procedures, check your private messages.

http://img179.imageshack.us/img179/566/4t60ewx8.jpg