No. The transmission on the 91-94 Explorer is well known as the weak spot for the truck. Failure is so common that you can find the transmissions on eBay.
My '92 is on the third transmission. The second one, direct from a Ford dealer and over $2400, lasted less than a year.
with mine the transmission was going out and it could be something as little as a bolt or as big as the transmission itself (my ford has 227000)
The transmission is the same.
out the tail pipe
the transmission could be going out or slipping or your transmission fluid could be low
Sounds like a plugged catalytic converter. Sounds to me like the automatic transmission is not shifting.
The automatic transmission temperature sensor, on your 1990 Mitsubishi, is located on the top of the transmission. The sensor will have to electrical wires going to it.
The loud hum could be caused by some of the teeth going out on the transmission or that the transmission is failing.
Directly on top of the transmission. It has the shiny post going through the center of it and 1 electrical connection. Easily accessible
If you use the motor mounts off of the 1991 explorer also, it will fit and transmission should line up if it is same size motor. If going from a automatic to a standard, you will have to replace the flywheel.
Your transmission could be going bad
it starts slipping, highly recommend taking it to Ford service the sooner the better, less damage to the internal parts. Easy transmission for 2nd rate shops to mess up on.
Reading the codes is a good place to start.