One problem related to transmission not engage has been reported for the 2002 Dodge Ram 2500. The most recently reported issues are listed below.
Truck has 52000 miles, 5. 9l gas engine, 4 speed auto tranny, and has been babied, never been off-road or pulled a trailer. On 8/17/2007 I made a couple of short trips and when got home I went to back into driveway and reverse gear did not engage. It worked fine earlier that day, then nothing. Put my obd-ii scanner on it and no code, checked linkage and it is in proper working order.