Dies after it shifts

A new to us 1992 Gen2 3.0 4x4 with California emissions package. A three speed automatic, starts and idles nicely but once in "D" when it shifts from 1st into 2nd it immediately dies. Placing into "L" can drive as long and as high revs desired but as soon as you manually move it into "2" or "D"... it dies. Issue has baffled 3 dealerships, my old school mechanic has never seen anything like this in 35 years. Has anyone heard of such an issue with 2Gens? Working our way through it but now after many hours under the hood, looking for the forum advise. Grateful.

 

Tough call. I'm guessing you probably have the A340H transmission. That thing is known for being a pain. I'm not sure why its dying, but I would suggest maybe popping the pan off and replacing the shift servos. I've heard that is a common fix for a lot of the problems that transmission has. At the very least you'll get you some more fresh fluid in there which is always good

 

Any codes?