OK , after searching the archives looking for a story similar to mine ,well , here I am. Burned up the trans in my 92 Explorer helping people in the ditch after an ice storm here in lovely WI. Had a cooler on it , but abuse is abuse. Replaced it with one I took out of a 89 BII that looked identical. Everything was great for a while , then one day , turned a corner and it just "put itself" into neutral. Fluid looks fine. No slipping or warning of any kind. I don't know enough to figure where to look first (TCC, computer etc). I just can't believe that this is complete trans failure. Oh yeah , I replaced the modultor and read in the archives that older trannys don't necessarily "like" that. Help! a trip to the trans shop is like a trip to the doctor ; you leave poorer whether they fix anything or not! My gut instinct tells me this is electrical?

 

I seriously doubt it's electrical: the only electrical controls on this are 3-4 shift and TCC lockup, neither of which has any effect on how the trans operates in 1st, 2nd, or 3rd gear.

Out of curiosity, did you have that '89 2.9L A4LD rebuilt to 4.0 specs? Even though they are essentially the same transmission, the 4.0 version uses a few stronger parts.

Is the pump pumping? Disconnect a transmission cooler line, start the engine and see if fluid flows out at a reasonable rate. Be careful, that you know which way the fluid is flowing, and don't run the engine too long. You don't want to run the pump dry, just long enough to see if it's doing anything.

 

mrshorty , THANKS for ruling out the electrical end. i was actually hoping it might be as simple as a new control unit though. Oh well. The unit was bolted to a 4.0 when I removed it. The junkyard guy was also kind enough to tip the BII on it's side to facilitate removal. Not all are like that , eh? We didn't rebuild it , just put a new modulator valve on it and in it went. The one I took out did not look factory though. The torque converter was painted a pea green. Thanks again for your time in replying!