all 4x4 MJ/XJ/ZJ/YJ/TJ/WJ have versions of the dana 30 (some high pinion, some low, some with leafs, some with the CAD, some with CV shafts). what's weaker in the pre-95 axles is the ujoints are of the smaller variety. but that can be fixed with the shafts from a later axle (XJ/TJ). if you want to buy one that already has the joints, look for 95-99 XJ. TJ/ZJ will also go in but are low pinion if that matters to your build.