There is a whole range of automatic transmissions that you can transplant in. Novak adapters has some interesting articles, also Stu Olson did a nice write up on a AW4 conversion.
This should get you started and give you some ideas on what you might want to transplant into your ride.
I agree. 395,000 miles on my original. Three motors have tried to blow up my aw4. Lots of abuse. Only one trans service. Fluid stays clean. And I tow a small holiday trailer with it