Converter not locking up.

I bought an XJ to give to my Mom next year, its a 96 sport AW4 4.0L. It had 131K miles when I bought it and it has 142K now. Overall its in decent shape and the engine runs very well. When I bought it the tranny fluid was reddish brown and smelled a little burnt. I changed 6 quarts out with some valvoline Dex 3.

About a week ago I noticed that cruise control would not shut off using the on/off button. It would coast or disengage with the brakes. A few days later the torque convertor started disengaging while on the interstate once warmed up and would not lockup again until it was driven later in the day and it would repeat again. All this while using the cruise control.

I used the search function and there is not info on the "newer" models. I noticed most the problems are the TPS, NSS or Brake light switch. I put the multi meter on the tps this morning. Its a three prong with on being slightly shielded by small plastic tabs. So I tested that prong and the middle prong and the ohms changed in a nice linear fashion, checking both end prongs results in weird readings that were unreadable.

Next I checked the brake switch, it seemed to be working right with no sticking, all wires seemed to be fine also. So I drove it the 22 miles to work and right at 10 miles(warmed up) it started slipping, I didnt use the CC to see if that wa the culpret. So on the way home I didnt use the CC and it still unlocked was warmed up. I did test the CC and the on/off switch is working properly again. But its still unlocking anyway. Any ideas? I may change out the brake switch just cause.

i think your trans is done i have the same year xj auto and all i have always canged my trans fluid with nothing but mopar fluid only and have had (nock on wood ) probs i think it has to do with the fluid you used just a though i but allways hope for the best good luck

I'm not sure if its mechanical or electrical yet, I added the fluid about about 6 months and 10,000 miles ago so I'm not sure if thats it or not. My search yeilded alot of AW4 electrical issues.

after doing another hour of searching I found two other members had the same problem, tranny works fine, no TC lockup, it seems to be the failure of the #3 solenoid.

Flip94ta said:

I changed 6 quarts out with some valvoline Dex 3.

Click to expand...

It's not synthetic is it? AW-4's don't like synthetic.

no, its just dex 3, I am second guessing myself this morning and wondering about buying a TPS and trying it out. The only thing is that this problem only happens once its warmed up. It takes about 10 minutes to happen otherwise the lockup works fine. My friend thinks after its warmed up the fuild builds more pressure and the soleniod is failing then or the O-ring underneath is leaking under the pressure.

If the soleniod is failing wouldn't I get a CE light? I havn't had any lights yet.