Gm rear end

So, quick question my buddy has a 2005 GMC 2500 with the 6.0 gas motor. His rear end is in bad shape, instead of rebuilding the rear he was wondering what has to be done in order to swap a AAm 11.5 axle ? Are all the transfer cases in the early GM truck the same? Any help is appreciated thank you

Assuming he's got a 10.5 with 3.73s now, the 11.5 3.73 will bolt right in. Disc brake setups are close enough it's shouldn't cause bias issues (but remember the 11.5 rear disc centers are 4.84 vs 4.68 for 10.5.
Not sure if the driveshaft would have to be shortened or not.
Also not sure if the 10.5 uses the same ujoint as the 11.5, so research that, it's possible there's a hybrid out there for it.
That's all I remember....