I Have A 2006 Silverado That Has Started Changing From 2 Wheel Drive To 4 Wheel Drive On It's On. It Does Not Happen Often And Has Occured Ten Or Twelve Time In The Last Month. It Seems To Do It Most Often When I Start Backing Up. I Have Taken It Into The Chev Shop And They Say They Have Not Heard Of This Problem And That I Need To Show Them That It Is Doing It. I Wonder If Anyone Else Has Had This Problem.

My guess it is your actuator going out. It is under your battery box.

I Have A 2006 Silverado That Has Started Changing From 2 Wheel Drive To 4 Wheel Drive On It's On. It Does Not Happen Often And Has Occured Ten Or Twelve Time In The Last Month. It Seems To Do It Most Often When I Start Backing Up. I Have Taken It Into The Chev Shop And They Say They Have Not Heard Of This Problem And That I Need To Show Them That It Is Doing It. I Wonder If Anyone Else Has Had This Problem.
If you have the push-button 4WD feature, the switch is soldered poorly on alot of these pickups. You can replace it or pull it out and resolder it to see if it fixes it.

do you auto 4x4?

maybe the button is pressed and you didnt notice?

just a thought ......