Have you checked driveshafts? U-Joints in driveshafts could act this way.
There is a recall out on Chrysler Trucks, not sure if it covers the Commander for the Pinion Nut being machined incorrectly and allowing it to back out and have the pinion drift that could result in damage and sudden stoppage.
All Commanders had the same axles regardless of the engine/transmission. The Chrysler Corporate Axle. There is an optional axle front and rear for the ELSD that only comes with the QDII. The ELSD axles are the same axle just a little bigger carrier to fit the wider differential fitted with the gearotor pump and mounts an electromagnetic trigger.
The ELSD axles, having a wider carrier will have 2 extra bolts in the cover pan, than the standard corporate axle.
The ELSD, the E stands for electronic, needs the QDII electronics to work, I would avoid getting that, since you'll never get it to work for less than just buying a Commander equipped with QDII. Likely it would just create problems trying to retrofit it to a Commander it is NOT intended for.
The 2005-2010 Jeep Grand Cherokee should have the same axles and driveshafts, BUT I'm NOT positive on that, you'd want to check it out before actually purchasing. i.e. compare part numbers.