If this ^ doesn't help, the only other simple thing I can think of a defective Brake Lamp Switch - TCM contacts - which are normally closed, providing a ground to the TCM and PCM, and when the brake pedal is applied about 1/4" - 1/2", the contacts open, killing the ground circuit.

When the brakes are applied, you will loose Overdrive (TCM) and Cruise Control (PCM).

Some people have diagnosed a defective Switch, or sloppy brake pedal linkage, by driving the Jeep at around 50-55 MPH and pulling back on the brake pedal with their foot and seeing if OD is achieved. This is not a conclusive test but worth trying.

There is a pin cavity (23) in the TCM connector for the Brake Lamp Switch Sense but I've yet to figure out a way to effectively test the input, resistance or voltage wise.

The Brake Lamp Switch contacts can be tested but the only way I've been able to test it was to remove the switch. But going through the hassle of removing it and reinstalling it wasn't worth the effort so I just replaced the switch.

If it is not the switch then the only other thing I can think of that's field replaceable is the Trans Valve Body, and if this doesn't fix it the fault could be in the trans itself.

 

Funny thing is the cruise will not come on. Noticed that after i bought it but never thought twice as i dont use it.
So might be brake light switch causing them both? It wont even power on (cruise control) so assuming it has no power or ground

 

Could very well be.

 

brake light switch is on its way from morris 4x4.

Will post when it is swapped out

 

Swapped brake light switch and it was not it.

Thinking now I need to swap in my low mileage rebuilt tranny and new torque converter as im out of ideas.......

Thanks for all your help KEN

 

So after I pulled the tranny to swap in a low mileage rebuilt one I noticed it had different harness connectors so could not install it.
I did however swap the Torque Converter and reinstalled the old tranny.

Test drove 5 mins ago and still no over Drive.

So:

1. Solenoids ohm out good but were swapped anyhow
2. TCU has been swapped back and forth with another 98
3. Brake light switch swapped
4. Torque converter has been swapped

Any other ideas? Bought ready to part it out.................

 

I have Cherokee Model 98, Automatic problem not work Overdrive , does not work Overdrive I'm changing : TPS, Computer (controller for TRANSMISS )next to the pedal inside, Brake Lamp Switch Sense ,

Reset cable Transmission in throttle

Thanks