My 95 motecarlo wont shift into over drive just changed filter

overdrive is the fourth gear.D1,D2,D3,D4 now drive truck at 80 kmh
cruise at steady speed no fuel pedal movement, downshift from D4 to D3 you should feel RPM raise .. after push brake pedal a little you should see RPM raise 300 to 400 rpm.
shift pattern is 1st gear ,second gear,3rd gear and lock up(torque converter clutch). 4th gear with lock up
hope it helps

Shift module internal to trans is not functioning properly. Take it to a good independent trans repair shop. Usually, for any internal, the labor is so high, esp for a 4wd, that you replace it with an entire reman trans. with a warranty.

change trans fluid @ filter first, does it still drive ? if it does I'm thinking a stuck valve. was it acting up like a bad step child before this ? you know, its free to have a trans shop test drive & inspect the trans , thats what I would do. they'd know real quik. save you time & stress.

new transmission will be needed more than likely. But i have had luck with a few cars with similar problems by changing the trans filter and fluid

It's possible, especially if the used trans sat unused for a while. When you change the filter, make sure that the trans has fresh, proper fluid.

change trans fluid and filter check speed sensor on trans

start with filter under trans. pan replace with new fluid add "lucas brand trans fix" this may clear up a sticky trans. valve if you are lucky but be ware if it works it could be a temporary fix

When it shifts to third does it just feel like neutral? If yes it will need rebuilt again, you hurt the 3/4 clutch.

hello i would take a chance and change the vacum modaglator.for about 20.00 bucks. its real easy.also u can check to is if there is vacum at that valve. p.s it is located on the tranny just above the pan

change the shift solnoids should do the trick