TCU location and troubleshooting

[swampbrat]

Car : 88 gl10 sedan turbo EA82 awd. Tranny 4eat , started slipping or possibly just dropped out of gear on highway , looked a little low on fluid, went and added some more ( a little overfull ), 2oo yds down the road same thinf. It now won't run - stalls motor like torque convertor won't unlock. A member with a good trans told me it could be tcu. Where is it at and what can I do to test it. I may need to purchase a good one and am not sure if I also need to get another trans shipped from KY or what. Car is already in friend's garage up on jackstands. I understand tc solenoid is opposite the others on valve body - could I unplug it from harness without opening pan and see if it will run?

[presslab]

The TCU is located behind the rear seat, on the driver's side, just below the window.

 

Unplug the TCU, the tranny should work in failsafe mode, 3rd gear with the AWD clutch locked, torque converter clutch unlocked. If the engine still stalls it's not the TCU.

[idosubaru]

even easier is to unplug the trans harness in the engine bay, one plug, no trim or anything to remove.

 

was this car worked on previously? sounds like what happens when an engine/trans is installed incorrectly and the trans pump is cracked. was there a recent engine/trans removal on this car?

 

or was it running perfectly fine prior?

[swampbrat]

I don't think it was ever removed. It onhly has 124k on it and spent 7 yrs sitting in a field. We have driven it to California and back with no problems. I will test the tcu this afternoon.

[swampbrat]

the latest drama from Evan's garage... with the engine off , the dipstick read way overfull , I drained probably 3 qts! (?) I tested the ECU ( ok ) with fluid let out it would start and run. Changing blown hose under intake was an ordeal but it is done. I think I got the tranny fluid level just right and unhooked the battery so everything is probably reset. I changed the turbo coolant hose while I was at it and it seems to drive great. Will check on the highway when I have more time. My Samurai is now fs on ebay , hoping to score a dual range wagon to replace it if you know of one.

[987687]

The AT should be way overfull when the engine is off. The torque converter drains when the engine is off, but when the engine is running it fills back up again. This is why you should always check the tranny fluid when the engine is running. You'll only get a correct reading with the engine running and the transmission warmed up.