1991 Chevy Transmission won't go into O/D

Do you feel some play between the linkage parts?
If it's too much play, then that's the problem

linkage is binding near the shifter base.

Jack up front end, and put on stands. Remove wheel. Remove large nut on end of drive shaft. Remove lower control arm, from wheel hub bearing assm.
Push drive shaft back toward transmission.
Now that drive shaft is free, you must "pop" it out of transmission output.
You can use a pry bar, but be careful not to damage anything.

alot of good librarys carry manuals

It's the white bushing on the end of the gear shifter can be fixed easily from inside the truck. Just remove gear shift leaver an it's on the end.

Rebuild the transmission

Check the fluid in the the axle. Also make sure the brake isn't locking up. You might want to take the axle gear cover off and see if the "C" clip came off or is broken on the gear assembly. Almost sounds like the differentials is locking up.

start the vehicle, shift transmission to nuetral. then move the 4x4 shifter to the 2wd position. then shift the transmission into reverse and back up a few feet straight, then drive forwards. it should be out of 4x4.

If the overall length of the tailshafts are the same, If I remember correctly, you can just swap the tailshaft housings.In some cases though, the output shaft needs to be swapped as well. Check with any transmission shop and they can tell you for sure!

rebuild the original, a 95 wont and cant work, and it a 2 wheel drive if the shaft is too long... www.TransmissionGarage.com