Very hard to selector gear

1991 Pickup - 4 cylinder. 145,000 km. automatic.
Recently the column mounted gear selector has become very stiff to put into gear.
I've released the linkage to the side of the transmission, than the selector is easy to move.
It seems the resistance is inside the transmission.
Any suggestions??

Cheers
Jp

Do you know what modle trans you have or what your vin is, If you get back to me today I may be able to help get some info for you.

nate

Do you know what modle trans you have or what your vin is, If you get back to me today I may be able to help get some info for you.

nate

Don't know the model, but it's a 4 speed auto w/ overdrive switch (off/on) on the top of the selector.
JP