Edmunds Answers

Voted Best Answer

  • avatar craig70 11/20/12 3:53 pm PST

    I'll try and help ya out here. If you have a manual for the jeep you could look and make sure your wiring harnesses are the same by looking at a wiring diagram. I have a '97 grand ch. 4.0. First pull off the windshield washer fluid jug on passanger side. Now you should see 3 plugs plugged into an electrical terminal (its actually the control module) located on the firewall. Unplug the plug to the far right(towards driver side) You want to splice 1 end of the thermistor into the Black with blue stripe wire. You will need to strip back and cut some of the harness to expose the wires. The other end of the thermistor needs to be spliced into the middle plug. The wire color on the middle plug is the violet wire. I hope this helps. I took a picture with my camera phone, but didnt turn out soo well. Good luck.

Answers

  • craig70 11/20/12 3:53 pm PST

    I'll try and help ya out here. If you have a manual for the jeep you could look and make sure your wiring harnesses are the same by looking at a wiring diagram. I have a '97 grand ch. 4.0. First pull off the windshield washer fluid jug on passanger side. Now you should see 3 plugs plugged into an electrical terminal (its actually the control module) located on the firewall. Unplug the plug to the far right(towards driver side) You want to splice 1 end of the thermistor into the Black with blue stripe wire. You will need to strip back and cut some of the harness to expose the wires. The other end of the thermistor needs to be spliced into the middle plug. The wire color on the middle plug is the violet wire. I hope this helps. I took a picture with my camera phone, but didnt turn out soo well. Good luck.

  • Stever@Edmunds 11/20/12 3:59 pm PST

    You can reply in this thread by clicking the Answer this Question button and that will help keep all the information in one spot. Thanks!

  • tbone55 11/21/12 12:39 pm PST

    Hey Craig 70 thanks a ton!! I'll be trying this as soon as I can get
    the new thermistor.

  • tbone55 11/21/12 3:36 pm PST

    soo, Craig70, I called 2 different jeep dealers and they tell me there is no thermistor or temp sensor for the 42re, only the solinoid or pressure sensor. What type of thermistor did you use and where from?

  • craig70 11/21/12 5:39 pm PST

    Well, I am not sure what to tell ya on that. I have the 42re transmission and I recieved the thermistor from a friend who worked on these transmissions, and there is definitely a thermistor or temp sensor, it is shown in the wiring diagram. If they dont sell the thermistor seperately, it may be contained in a sensor kit you need to buy, either solenoid or pressure. If I were you I would take the picture posted and show it to them, or just try to buy any thermistor that could work( make sure it is in the -10 to 220 range). All it is doing is sending the temp at the thermistor back to the module to let it know it is within operating temp range. Might be able to get one from any parts store, radio shack...etc.I have a feeling it is contained in one of the 2 sensor kits you mentioned. I am not a mechanic, just know enough to be dangerous! Hope this helps, and maybe call a jeep dealer and talk to a mechanic there, and I bet he/she could tell ya a little more about the temp sensor and which kit you need to buy to get it, or if you could purchase an aftermarket that would work.

    Have a great Thanksgiving.

  • tbone55 12/06/12 9:04 am PST

    I'm baaaack! Sorry for the long absence, but I've got some good excuses, including but not limited to the thanksgiving holidays and my mother-in-law becoming really ill and dying! Anyway, back to the shifting problem. 2 weeks ago I decided to take my jeep to a very reputable tranny shop to see if they could provide a diagnosis.
    The tranny tech hooked up his computer and we went for a ride to see what it would tell us. Everything was fine for about five miles of
    driving fanywhere from thirty to fifty mph to get the tranny to shift in and out of O/D. After shifting in and out of O/D several times w/ no problems, you could tell the tranny really didn't want to shift into o/d again. The rpm's had to go about 500 higher than before and the o/d kind of slammed when it did engage. The comp said the fluid temp was 160 something, so that eliminated the thermistor
    as the problem. The tech said all the electonics were working ok, so he was guessing it might be a seal problem or something. I went ahead and made an appointment for them to work on it the following week. Over the following weekend (before the app't) the husband of one of my wife's friends who I had never met called and says I hear your having tranny probs w/ your jeep. I explained the issue and said he was quite the mopar freak when he was younger
    and that it sounded like a piston was hanging up. Apparently they run hot enough that they sometimes get a build up of varnish that'll
    make pistons and such hang up inside the tranny. "Just pull the parts out, clean the varnish off and your good to go". I wasn't going to
    I wasn't going to tackle this, but I figured what the heck i already have an app't at the shop, so why not. I drained the pan (very carefully) and took apart the gov.sensor block which includes the gov sensor and the gov solonoid. This was pretty easy but I found no probs with it.(and saw nothing like a piston that might slide back and forth) After another 3hrs on the computer I decided to have a look at the 3-4 accumulator piston.This is located under the flat plate on the drivers side of the valve body. It's a flat plate w/ about 5 screws in it and a hook that helps secure the wiring harness for the gov sensor. Remove the screws and the accumulator piston and spring will just about fall out of the body. There is a spring that holds the piston in place to help cushion the shift into o/d and the one in my tranny was broken right in the middle. Can't buy one of these at a reg parts store, so I just stopped there and decided to tow the jeep to the shop and let them finish the job. They didn't find anything alse wrong and charged me $100 to finish the job. That's about $400 less than I originally thought it would end up costing me, and the jeep shifts fine now! I never new a $5 part could cause so many headaches, but I'm back on the road now! hope this helps others and thanks for all the info from everyone, especially you Craig 70!

ADVERTISEMENT

Top Transmission Overdrive Experts View More

Rank Leader Points
1. MrShift@Edmunds 205
2. karjunkie 150
3. laltazan 70
4. zaken1 60
5. craig70 50
6. texases 45
7. Stever@Edmunds 35
ADVERTISEMENT