ok, so assuming: i use a cast iron OD case which should have the larger bearing and largest bearing retainer, the cast iron tail housing already on my transmission, and what is presumably a cast aluminum side cover, the only details left to be figured are whether or not i need a different rebuild kit for the cast iron case, and whether the or not the counter shaft are the same from the cast iron OD and the aluminum OD, and if not what the work around would be...any input on the last one?