I have an 03 Durango 4.7 with a bad engine. (bad rod bearing) Found another 03 with a 5.9 and a bad transmission. (rear piston broke) Are the transmissions interchangeable? OR on the rear piston issue: can this be fix in the vehicle?
Thanks,
Scott

No Trans people?

I think the transmissions are different from each other, and I would fix the 4.7 if it were me.

The transmissions are different between the 5.9 and the 4.7. The wiring harness and computer are also different between the two drivetrains, and if the 4.7 is anything like the 5.7 as far as motor mounts, they are also different between the 5.9 and the 5.7.
We swapped a 5.7 into an old car that had a 5.9 and we had to change everything, nothing interchanged. Gene

I'd drop a 5.7 in the 4.7 truck if you want to keep it. One of the Dakota guys did that swap years ago and the 4.7 computer ran the 5.7 fairly well.