I picked up a 99 with a 5.4 l engine with a bad automatic trans in it. case is cracked it is the 4w70 model tranny with electronic 4wd. Is this a common issue for these trans to crack there cases? it is cracked just prior to the portion in the back that connects it to the transfer case. Just curious as I am most likely gonna just put in a used replacement tranny to keep my cost down.