I don't think there is any 4x4 issues because I use it every couple of months just make sure it is still working. The truck got dropped off at the shop Saturday morning, but I haven't heard anything yet. The initial suspect that both my usual Ford tech and the transmission guy came up with independently was some sort of output or input shaft - something that feeds the transmission I think? I was also curious if maybe there couldn't be some issue with the torque converter? Something in the torque converter or that input/output shaft that feeds the transmission made sense because that would affect both the rear end drive and the 4x4 correct?

 

Finally an update from the transmission shop - it was not the transmission. The transfer case range gear broke - whatever that means. I'm not really sure how or why that would happen, but he said it is considerably cheaper to fix which is always good.