Compared to A-bodies they are hard to find parts for.
Many variations on the drivetrains.
The front Dana 44 differential got moved to the driverside in 1980. For 83 and 84 with automatic transmissions, there was a front axle disconnect. The housings and axles are limited to those years. The automatics in 1985 - 91 have no disconnect. These axles are 'hubless' - in otherwords the axles always engage with the wheels. Axles and housings for pickups (J-trucks) and Cherokee Chiefs and other 'wide track' optioned wagons are wider. Manual transmission got manual locking hubs.