The axle shafts (Dodge calls them driveshafts) are the same for Left and Right sides for the 7¼” as well as the 8¼” (but different between the two different size differentials) FMJ differentials.
They are also the same (for each side) for the rear differential on the 2002-2007 (KJ) Liberty’s – so the carrier offset will be the same.
The Liberty’s came with the Chrysler design 8¼” differential as well as Dana 35. The Dana 35 has a 7¾” ring gear so my opinion is the Chrysler 8¼” version is stronger (but others might disagree with that).
They come in drum brake and disk brake versions – with disk brakes are far more common.
The width (where wheel attaches to drum/rotor) is 63-3/8”. FMJ vehicles are 59-3/8” drum to drum – which makes the wheel attachment point 2 inch (50 mm) wider per side.
The Liberty’s do not use leaf springs – so the attachment brackets will need to be cut off of housing and new leaf spring perches welded back on. New perches are fairly easy to find.
The axles also use 5x4.5” wheel bolt pattern (same as FMJ’s) so existing wheels should still work – providing there is no tire to chassis contact anywhere.
Liberty differential ratio options are 3.73 and 4.10 (and maybe others?) and they come with or without limited slip. The ring and pinion gear set will interchange with most if not all Chrysler design 8¼” differentials.
The carriers and axles have a different axle spline count than what FMJ vehicles use (27 vs, 29 spline, I think). Axles are a different width so no issue there – but to convert a Liberty axle to limited slip, you will need a ’97 or newer 8¼” or newer carrier.
Liberty’s also use a different differential yoke. A person can either remove and reuse the yoke from your existing FMJ or convert to the newer style design.
The data for the 2008-2012 (KK) Liberty’s has not been obtained – so not sure about them, yet.
BudW