TC brake switch??

Lately my trans has been sticking in OD when I let off the pedal. It holds in down to 30mph sometimes until I tap the brake.
I'm hoping it's not the solenoid, but haven't tested the TPS since I don't know how, though it was all cleaned along with TB and IACV a couple months ago, connections dielectric greased, pins and all. Seafoamed it too after a can of mopar comb. chamber cleaner so that area is clean.
I also recently changed to AT4 ( A few XJers said it's the same as dexmerc3 supposedly PLEASE correct me if they're wrong!))

I've heard there is a torque converter related switch near the brake switch. Does anyone know where it is what it looks like, and how to clean or fix it if possible?
Are there any other possibilities?
I get no CEL and the OBD is just 12-55

96xj 146,000 AW4

anyone? I've searched and searched but can't find anything on the switch. Just tired of getting stuck in OD...

You are using ATF +4? If so, it is not the same as dex/mer 3 and they are in fact wrong.

Talyn said:

You are using ATF +4? If so, it is not the same as dex/mer 3 and they are in fact wrong.

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What he said.

But yes, there is a switch that will autmatically unlock the TC when the the brake is depressed. It is possible that it is stuck, but it's usually the opposite problem. Most of the time, the tranny keeps dropping out of OD or switching back and forth. It also kills your cruise control.

Anywho, you can just follow the brake lever up to the top and you'll feel/see the switch. On my '94 its just a little black box with some wires coming out of it and a push button switch on the other side.

But I tend to think it's the ATF+4 that is causing the problem.

I was running DexMerc3 before and it was doing it then too. i just switched to atf4 less than 150 ago. I'm gonna switch back ASAP though; no sense taking chances.

Just spoke to the dealer and as I though ya'll are right.
is it okay to mix n match if it's all DexMerc3?? I have a quart of Valvoline high mileage DM3 and a quart of reg valvoline DM3. I'm gonna get more high mileage, but wouldit be okay to dump the reg in. Just checking. Probably doesn't matter. Those couple qts of ATF 4 in the bell won't hurt will they??
Besides the brake switch, any other possibilities for a hyperactive OD gear??
thanks for all yer help BTW!!!

I believe on a 96, the brake light switch is used for the input to the trans computer. The older Renix (pre-HO) had a separate switch. Sounds like your switch is working since it does unlock when you tap the brake pedal.

The TPS could be the culprit as the trans computer uses that as an input to determine t/c lockup as well. When you say cleaned, hopefully you didn't get it wet. The TPS sensor on the HO setup is notorious for going bad when pressure washed or dunked.

I'm skeptical that the ATF4+ is the cause. Usually if ATF4 is a problem you get excessive slipping and heat. There have also been plenty of reports that ATF4+ works fine. I'm probably just do a normal drain and refill which changes the majority of the fluid and don't worry about it unless you note a lot of slipping.

Your friends probably thought it was a Chrysler auto tranny which woulld indicate ATF4+, but the tranny is in fact a Toyota tranny made by Aisin Warner (hence the AW4).

BTW, Lawson is correct about the switch. It has three sets of contacts.

Matthew Currie said:

BTW, Lawson is correct about the switch. It has three sets of contacts.

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Hallo. A pic of the inside:

click for bigger pic.

'92 XJ