Kress, I was just thinking they would be tearing up trannys way before cracking blocks. I dunno, thought these diesel blocks were more bullet proof than that. I know the Chevy diesels were cracking the heads at 60 k miles, but they were a gas motor converted to diesel basically. Well this all kinda worries me cuz I have a 7.3 in my wifes Excursion also. and it also has the chip in it. I may take them out till I have some more info on all of this. Don't wanna have to buy too many new engines for these vehicles ya know. Thanks, Mike...