One problem related to transmission not engage has been reported for the 2001 Chevrolet Silverado. The most recently reported issues are listed below.
Received letter from gm regarding possible engine light coming on. When it did come on several times, went to dealer, and they replaced fuel pressure regulator on gm. A month later, at freeway speeds transmission failed and went to neutral, almost causing an accident with several trucks. Limped home after several occurrences of same thing by stopping and totally restarting and moving on until another failure. (approx. 15 times) went to dealer and gm now replaced the injector pump assembly. Brought the vehicle home, parked it for 5 days and then started it up the transmission wouldn't engage and then suddenly "clanked" into gear and then disengaged into neutral. Stopped engine, restarted and then drove to dealer, who said gm wouldn't participate, saying it was now transmission problem and no longer warranted. The dealer installed a drain back kit in the transmission at my expense. The dealer had a bulletin from gm regarding this very problem. It is my contention that the engine (fuel pump regulator, injector pump assembly) problem put exsessive pressure upon the transmission and the computer kicked it into neutral causing the failure of the drain back, requiring a modification kit. I contacted gm, explained the situation and they flatly refused to participate in the repair.