My auto trans is not downshifting..help?

[Ollie]

My 1989 Comanche 4.0L stock transmission is not downshifting while driving. 

This really became obvious to me on our trip to Pigeon Forge, TN. It would downshift out of the lock-up torque converter.

When you stop, it downshifts and up shifts on acceleration, but only up shifts at the shift points no matter how much fuel you give it. The trans shifter linkage appears to be adjusted as it goes into reverse and all other gears with the pointer lined up. 

This is what I have done

1. Changed trans fluid and filter. The fluid was red and had no burnt smell, no crud in pan
2. Wired the inop comfort/power switch to power..it was burnt and inop
3. Checked all fuses, 7.5 amp in fuse box and 10 amp in-line fuse next to the trans module, they are all good
4. Un-plugged and cleaned trans module plug in
5. Checked the trans kick down cable, it moves the complete travel when accelerator is to the floor, it has tension on it when disconnected off the linkage and you pull on it.
6. Cleaned the one electrical connection I could find on the trans

I did some online surfing and I see the trans module is not available, at least at local part stores.

 

Any advice on what to do next is appreciated.

Having Comanche Fun,

Ollie

[jdog]

Adjust the tvs, or what your calling the kick down cable

Check the tps:http://cruiser54.com/?p=54

Clean the trans connector:http://cruiser54.com/?p=58

[scaleless]

From my understanding the TV cable (the one you mentioned being tight, going from the throttle to the transmission) controls shift points, and the automatic TPS controls downshifting when you give it gas.  Like Jdog mentioned, check the TPS. As Cruiser mentions on his site, the 4-wire connector feeds the TCU and the 3-wire connector feeds the ECU.  Make sure its adjusted properly and that the signal is getting all the way to the TCU.

[omega_rugal]

6 hours ago, jdog said:

Adjust the tvs, or what your calling the kick down cable

Check the tps:http://cruiser54.com/?p=54

Clean the trans connector:http://cruiser54.com/?p=58

 

the aw4 doesnt have a throttle body cable

[jdog]

26 minutes ago, omega_rugal said:

 

the aw4 doesnt have a throttle body cable

I believe it does

https://www.allpar.com/d3/SUVs/jeep/cherokee-transmission.html

[omega_rugal]

oh i thought only the 42rh had it, my bad

[Ollie]

Halleluiah...Halleluiah !!!!!!!!!!!  

 

I love hanging around a bunch of genius's....

 

Got my transmission shifting as it is supposed to. The issue was the TPS. When I first got my truck we changed it...but..I broke off one of the original mounting bolts and I tapped it out and put in a 1/4" bolt. To get the TPS to adjust as Cruiser 54 said, I had to use my Dremel and elongate and widen the slot to accommodate the 1/4" bolt. I adjusted and got the correct reading, following his directions. I was grinning ear to ear on my first test ride !!    

 

Maybe some day at a swap meet I can come up with a good throttle body. Any one know what years work on a 1989 4.0? are they all the same?

 

Having Comanche Fun,

Ollie

[jdog]

IIRC all renix years should work so 87-90 4.0 t/b

[cruiser54]

Nice job!!!