NHTSA Complaint #11519283 — 2011 CHEVROLET SILVERADO 2500

The vehicle started to shift on its own mostly between the upper gears even though terrain or load had not changed. At slower speeds the vehicle started to automatically shift into park and lock up the wheels. This caused a very serious risk of injury to me and the people behind me when it would lock up. After stopping the vehicle sometimes does not move when in drive. There are no warning lights Took it to a shop and they checked it over. I was informed that there is a known issue with the electronic transmission control unit (TCM) for the Allison Transmission. The issue is with the location of the TCM. GM has developed a new unit to replace the original TCM that is engineered to no be affected by this. But due to the demand GM has a back order on the new TCM. The cost to get a TCM has risen from $800 dollars to $5000 dollars if you can find one.