We were headed home from a camping trip, towing our fifth-wheel camper (medium sized). Stopped for a traffic signal, but when the light turned green, the truck refused to accelerate like normal. This happened totally out of the blue since no indication of trouble was observed prior. Then, after more pedal, the truck started to move slowly and we proceeded to the next light where the same thing happened again. By then, we were entering a very congested population area and already getting very concerned how much farther we might be able to go before total failure (still 30 miles from home via a very busy interstate highway). We then managed to pull off into a large parking lot and parked. It was then observed that the shift selector indicator underline bar was not visible on the dash display and the check-engine light was illuminated.

After all the anxious moments and all was said and done, the repair shop replaced the internal mode switch and the associated wiring harness inside the transmission housing and replaced the Transmission Control Module, which was trashed, as well. The cost shown did not include the tow bill, either. (After some research, it is suspected that the system had gone into limp mode and was probably stuck in third gear.) This has been a very reliable truck until this happened. Seems to me that the use of modern electronics has been the bane of the automotive world.