4 wheel drive locks up in reverse

What is your question?

2005 Chevy Avalanche I have a couple issues; 1. While in 4 (hi or low) and moving forward, everything seems fine until i make turns and you hear grinding sounds. 2. While in 4 hi or low and trying to back up, the truck will move for a few feet then the wheels lock up.

What makes this problem better or worse?

leaving the truck in 2wd makes the issues go away

How long has your 2005 Chevrolet Avalanche 1500 had this problem?

just noticed it this month. never really needed to use 4wd before.