2006 Chev Silverado 1500 - 4WD Issue

[Fishinguy40]

Saturday I put the truck in Auto 4WD, as some of the streets and my daughter's driveway still had snow. As I left the subdivision where my daughter lives there was a couple loud clunks. It felt like the 4WD engaging/disengaging. When I looked down at the 4WD button it was in 2HI. I am positive I left it in Auto 4WD. Truck seemed okay rest of the day.

This morning on my way to work, truck was still in 2HI (per the indicator light). I made a left turn on dry pavement and it sure felt like it was in 4WD. I switched from 2HI to Auto 4WD back and forth a couple times and it seemed to function (per the lights on the buttons) but I could never really tell if it was or was not. I am concerned because the clunks on Saturday were loud. You could hear them and feel them. There were no flashing lights or anything on the dash or 4WD button. I know that these 4WD buttons can be the cause of issues. Any thoughts?

[Stcloudangler]

I have the same model as you, and had to replace the actuator chip in the transfer case. It got stuck in 4 low and the switch went out. A common problem, I was told. He also said that the auto 4wd feature was something to avoid. It puts added stress on the transfer case, just use 4 hi and 2 hi.