CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Automatic transmission lock-up problem

The lock-up clutch in the automatic transmission in my 1998 Jeep Grand Cherokee will momentarily and randomly disengage when driving at a steady speed on level roads (initial discussion approx 1/9/09) and I would like to buy a good transmission book/manual to check-out/investigate some of the possible causes suggested to date. Please inform me where I can find this type of book/manual.

Before going through all that, make sure the brake light/interlock switch isn’t the problem.

You know that when you step on the brake pedal the lock-up torque converter disengages? If you have a switch that’s effected by vibration and turning the brake lights on and off, the same thing happens with the torque converter clutch.

Tester

Thanks for your suggestion - how can I determine if this is the cause of my problem?

The next time the TCC starts disengaging, slip your left foot behind the brake pedal and lift up on the pedal. If the TCC remains engaged there’s a problem with the brake light switch.

Tester

Why did you start a second thread on the same subject? We addressed the brake light switch in the last thread…

transman

I appreciate the suggestions on my first question (i.e. disengagement of the the lock-up clutch) but now I am searching for a suggested transmission book/manual that I can use for following up on the initial suggestions and troubleshooting techniques.