Hey guys I have a 2003 h.o. 3500 with the 48re. Truck has 70,000 miles and has been great till now. For the last 5000 miles when I put the trans in reverse the pedal is really stiff almost like a binding cable. Now here is what has me stumped it only dose it when the trans is at opreating temp(not cold) and in reverse. In drive trans and throttle works perfect. Trans has been serviced every 20k since new has no other faults. I pulled the cover off the tps and the culpret seems to be a cable that runs from the throttle to the trans. I've checked the cable itself and it slides smooth like it's suppose to. What could be causing it to bind only in reverse when the engine is running ???