How would you remove and replace the Automatic FWD transmission of a 1990 Chrysler LeBaron?

The question you ask is too involved for a proper answer. You need to go to a car parts store, and get a repair manual for your car. They cost about $16.00 Or, go to a Public Library.

It is a bit of a job but if you are doing this at home, I would remove the 'K-frame', this is the structure that the lower control arms are bolted to. The steering rack is bolted to this also. If you support the steering rack rack with wire, you can drop the frame quite easily. Once this is out of your way, you will have lots of room to remove trans. Disconnect battery , starter, axles at trans, remove flywheel to torque converter bolts, unplug any wiring to trans,(nuetral safety switch, reverse lights etc. Support trans with jack, remove bolts that connect engine to trans, lower tranny, make sure car is jacked up high enough to remove the trans.You may want to drain trans of any fluid. Make sure you use torque converter that comes with new tranny, also, shoud flush out cooler lines (they go to rad) and the rad. Most rebuilders use compressed air or a special aerosaol can designed for this. Any burnt tranny fluid left in system will shorten life of new trans, also chang filter in new? or used tranny. Ask a local shop what they would charge you for an install. .