If you still have all of the internals from the aluminum rear, they will fit into the cast iron rear. The internals from the aluminum rear are stronger and have fine splined axles. Also, the axles have studs on them - makes tire removal/replacement a little easier. The cast iron internals have a bevel cut ring and pinion, while the aluminums have a straight cut, so if you decide to switch these out, you'll have to change out the pinion shaft or swap the ring gears. I swapped everything for my 982, pinion and diff, and it works great. Just my
