The 4wd axles are an inch longer each side so using the stock parts you have 2 options cut and shorten the tubes to accommodate the 2wd axles (have to make sure correct spline count) Or Weld shut and re-drill the bolt holes to 0.600" (this is a much easier process and gives the truck a slightly wider stance) and while you're at it throw in some studs off like a 02 2500 because the studs are 20mm longer and have a pilot so lug nuts are a breeze to jam on, I would advise against the G80 as they are fragile, personally I'm running an auburn locker in a 4wd axle that has been redrilled and I'm extremely happy with it