Blazeorange

Ok. so I have a 88 Cherokee limited. It has had transmission issues since I bought it. It had the trans rebuilt 6 months before I bought it. If I drove it in normal mode it would hunt and sometimes not upshift out of low gear. If I drove it in power mode it shifted fine. Took it to a transmission shop and they said it was the tcm. I replaced the tcm and now it hunts even in power mode. also sometimes doesn't shift into high gear. sometimes gets stuck in gear and when letting off acts like a compression brake. don't know if the tcm is the issue or transmission. If I disconnect the tcm and manually shift it drives fine, but never gets to high gear. Please help. can't afford another car.

peep

Do you still have your original TCM?, plug it back in and run in power mode where it shifted fine.
Your trans pan has a drain plug. Drain and exchange the atf fluid (use Dexron type), this won't be a full exchange, there are other full exchange methods that involve some running while simultaneous fill and drain but are complicated, google those and consider), sorry for ramble, a partial fluid exchange is still good, and pulls some debris, if present, from your pan. This is an easy to-do. You arn't changing the internal filter by this method but those filters are bascially screens and not commonly blocked. If the PO truly had a trans rebuild prior a fresh screen would have been installed, but remember anything the PO did or says is suspect.
The shift is solenoid controlled valves, if the solenoids are weak or the valves are gummy, shifts can be effected. Pressure is one of the trigger mechanisms for the valves.
Fluid exchange is a good method to transition away from any gummy conditions.
Beyond that you will get into pan removal, solenoid replacement, valve body removal and cleaning and rebuilding, things get more complicated.
There are more knowledgeable members in the forum. Take all our advice into consideration, decide what makes sense, and try some suggestions, then give some more feedback.
There is so much info in the forum, perhaps some additional searches of other trans shifting related threads will give some additional answers to your situation.
All the best of luck to you. Of course your 89 Chero was the very best year!

cruiser54

Click on the link below and do Tip 10.

Make sure the "trans" fuse isn't blown in the fuse box.

Also do this:

Bypassing the Power/Comfort Switch on a Renix Jeep

Remove and unplug the switch. In the harness are 3 wires One has a stripe, one is tan, and the other black. Make a 4" jumper wire with a male spade at each end. Plug one end in the cavity for the tan wire and the other in the cavity for the striped wire and you'll be in permanent Power mode. Stuff the harness back in and reinstall the switch for looks.

If you happen to have a 91 or 92 XJ/MJ and it has the Power/Comfort switch, just jumper the Tan and Blue wires in the harness plug.

NEVER include the black wire when jumpering!!!