I installed a Flowmaster Force II exhaust kit on my 97 4.6 4x4 this weekend. The kit pipes are 2 1/2 " and I ran them out the back. I only have about 1 1/4" inch clearance from the pipe to the center of the rear diff. I jumped up and down repeatedly on the bed and didn't hear anything and my disinterested girlfriend said it wasn't hitting the diff but I'm still I'm concerned they will be in contact, especially in offroad conditions. Anyone ever encountered this problem? 1 1/4" clearance is the best I can do with the current set-up and I really don't want to have to lift the rear end. Thanks.