Ok I have a 2013 f150 4x4, I bought wheels online(yes I have learned my lesson and won't be doing that again). I bought a brand new complete set-tires, rims and new tpms sensors. I went to the dealer, they could only get the fronts to sync. So they told me if I bought the transmitter they wouldn't charge me for my time and I could try again at home. So I did, got home tried. Same thing I could only get the fronts to sync. I know theres a good chance it's that the sensors are bad. But I'm being optimistic that something is blocking the signal from the rear of the truck. I emptied my whole truck of tools and what not, tried again. Same thing only fronts. The only other aftermarket thing I have on my truck is LED tailights. Could that some how be interferring? I have contactEd the company and they are getting back to me. Any help would be great. Thanks in advance