[bntman]

Anyone got any info on how this works (sensor based, electronic vs. vacuum, etc.) as there is nothing in the manuals on torque converter lockup. Where is the switch that kicks if out when you tap your brake? What can make one stop? Will old or low fluid cause this? Low temperature? Mine has just quit locking in, and I'm trying to diagnose the problem.

 

[mwraight]

Knowing the year and make of your vehicle would really help -- but if it's a '91 or new Trooper or Rodeo it has a GM 4L30-E transmission in it.

The 4L30-E is electronically controlled and the torque converter clutch is solenoid controlled.

This is a good website with info about troubleshooting and repairing 4L30-E's: http://www.transtec.com/rebuilder_news/2nd_q95r-n.pdf

Good luck.

 

[bntman]

Yeah, it would, wouldn't it...

1988 Trooper 2.6, I have no idea what tranny. It did start working again the other day. I'm curious what makes it kick in and out though, in case it stops again for good (which I fully expect)...

Thanks.

 

[JTK]

A modern electronic AT measures coolant temp, ATF temp, engine speed, and vehicle speed- and locks/unlocks the TC accordingly. Cold coolant temp will prevent the TC from locking until the engine warms (an emissions control thing). High ATF temp will cause the TC to lock in third & fourth gears to reduce TC slippage & bring the heat load down. The soleniod assembly that locks the TC can be replaced from whithin the tranny on some, others the TC needs to be replaced.
G/luck
Joel