Why wont my 1989 cherokee pioneer trans wont shift automatically

how many miles is on the trans, what condition is the fluid in (red, brown, black, burnt smell, metallic shavings, etc). could be shift solenoid for 3&4 or the trans could be going bad! if the fluid smells burnt, looks black, milky, or full or metal then the trans needs to replaced, or completely overhauled, all clutch packs, steels, solenoids, etc, and possibly sunshell, and planetary set!! Good luck hope its a simple solenoid and you can just drop the pan, change it out and be done! some trans have vacuum hoses that run shift points and such, but if 1&2 are fine then im thinking vacuum and TPS is fine! and the TPS will vary voltage as the butterfly opens and closes

check the tps(throttle position sensor)located on the right front of the throttle body.if its out of adjustment or going bad it will mimic a trans problem.

sounds like it could be the tps ,should check it with a multimeter.

its on the left side of the tranny towards the back

could be low on fluid or could be the tps(throttle position sensor)

sounds like 1 of the sincronisers in the trans is going bad ,take it to a trans shop to have them do a free check

Should be 6 bolts. 2 up top.

This is a standard shift I am presuming if so this usually indicates a bad synchronizer in the transmission. if it is an automatic trans. it is a speed sensor malfuctioning.

Bad trans module, or electronics in the tranny.

sounds like the governer gear stripped out , its located on the driver side on the trans where the axle inboard shaft goes into the trans