As you have both cars side by side you should be able to see any discrepancies. You can check part numbers on computers and other bits if necessary. I would expect it to be a straight swap.

If you know that one transmission is definitely good I would most certainly fit it (with new fluid and filter if it hasn't been done recently) rather than risking the "knackered" one.

In my experience (with out a lift and a transmission jack) the best way of doing an engine swap is engine and transmission out and in when they are mated.

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!