2006 Chevrolet Silverado 2500 transmission problems

Dt*: the contact stated while the vehicle was parked in the driveway with the gear shift in the park position, and without the keys in the ignition, the vehicle rolled forward and crashed into a parked vehicle. There was no warning prior to the incident and no injuries were sustained. The vehicle sustained minor damage to the front. The police were not contacted. The vehicle was inspected by the dealer who was unable to duplicate the problem. The manufacturer was not notified.

2006 chevy silverado hd diesel with allison trans-- transmission cooler lines leaking, dealer said there has been no known problem. I searched online and found hundreds of similar complaints. So I was forced to pay $700 to have the lines replaced, which will probably end up leaking again. This is obviously a defect, as I have 3 other chevy trucks, none of which have ever leaked from the trans lines, and some are over 10yrs old.