I hear a loud banging noise when i put my 99 Tahoe in 4 wheel drive
I had a suburban1999 5.7 when I engaged the 4x4 I heard the sound your describing, it was my transfer case. I never got it fixed and my car got stuck in rear wheel drive, it still worked. What I did to make the sound stop was make sure I was in 4 wheel before driving by pushing the bottom to activate it a few times, even when switching back to 2HI(two wheel) good luck.
It is a sliding drive shaft. This is a problem with the Tahoes and Yukons. It needs a special grease. Ask your dealer...he knows the problem.
Search Chevrolet Tahoe Questions
Chevrolet Tahoe Experts