william91xj

I read somewhere that the transmission works off of the speed sensor and tps so I was wondering since my speedometer doesn't work is that why my tranny will not shift on its own and I have to manually shift it? Any help greatly appreciated.

Lowrange2

I'm not a transmission guru by any means but my transmission shifted just fine when my speed sensor wasn't even installed.

cruiser54

I think your year has a fuse up under the passenger side knee panel for the TCU. It's wrapped in yellow tape and if it's bad/corroded you will have to shift manually.

william91xj

Thanks I will try that out and I didn't think the speedo would have anything to do with it either but I'm new to Jeeps and found it somewhere on Google but know I know where to ask my questions about them. Thanks alot

william91xj

I checked the fuse and the wires all look good so do I need to change the tcu

Turbo X_J

Start at the beginning, what happened when the transmission would no longer shift on it's own.

william91xj

It was like that when I traded for the jeep

william91xj

The Guy I got it from didn't know he said it was like that we he got it and the Guy he got it from told him it was the tcu. Just didn't want to start throwing parts at it until I knew the possibilities

Turbo X_J

Do you have access to wiring diagrams? Have you checked the fuse & circuit with a DMM? A new control unit won't fix it if the wiring is messed up.

william91xj

I'm sure I can find one somewhere and ill have to find or buy a dmm do I just check the wires in the harness to the tcu