This might end up being a long explanation but the more the better I guess. To start off I'm new to the forum, and Jeeps! I have a 1996 Jeep Cherokee with about 200xxx miles on her(4.0 I6 engine AW4 Trans). Unfortunately, the trans was started to go out. It was leaking everywhere, metal shavings all up in it. But here was the real issue, and the one I continue to experience, the Jeep likes to start in 4th gear from a stop. At first it would happen intermittently, and topping off some fluid seemed to do the trick. So I chalk it up to the trans going out and decide to have a shop rebuild it. For the first day driving around she was great, no issues, but wham! The issue popped up again. Same thing, starts in 4th gear from a stop. shifts fine when I put it in manually (1-2 on an auto trans). So it has to be some electrical issue right? Other people have said the TCM is the problem, so I went ahead and threw a new one in there, and nothing. Now in the beginning the issue would happen on and off, but since the trans been rebuilt it is constantly having that issue. I had asked the shop to take a look at the wiring and they said it looked fine, they tested it, and they said it was fine.

Am I missing something here? Im stumped, and to be honest; don't have a lot of faith in that shop. Its my daily driver, so I've resorted to manually shifting it, starting in first and skipping second because it wont make the shift unless its at 4500 rpms. I pray I'm not damaging the transmission doing that. You guys have a lot more experience than I do with Jeeps and cars in general, what can I do?

 

Most likely electrical. Possibilities are:
- Bad #1 solenoid, which would also affect 2nd gear.
- No power to the TCM causing it to have no solenoids engaged, giving 4th gear
- Bad TCM, very rare.

Test the resistance to the solenoids from the TCM connector. Pins C14, C15, and C16 should be 11-15 ohms to ground. The TCM is located under the passenger side of the dash, below the glove box bolted to the front part of the dash. Verify that with the key on, the TCM is actually powering to D14 and D16. With it plugged in, backprobe the connector and verify you have +12 volts going to solenoid #1 to command 1st gear.

 

I took it to a shop and they tested it, said it was a pinched wire that was causing the TCM to go off and on. Got it all fixed now Thanks for your help. Hopefully next time Ill have the means to do it myself but now I know what to look for. Thanks again.

 

Good on the shop for tracing the wiring problem, instead of immediately suggesting a transmission rebuild.

 

They already rebuilt it haha, next time I'll do a little more research into the wiring. There was metal in the trans fluid, but maybe I could have ran it for a while longer if I had just solved that wiring issue. Oh well.