4wd noise from a 97 Tahoe

I've got a 97 tahoe LT that has 102,500 miles on it. When I engage the 4LO from either 2HI or 4HI there is a single loud clunking sound. It only happens when I go into 4LO, otherwise its quiet while driving in 4LO. Had a retired mechanic that I trust listen to it while I shift, he suggested that I take a look at the front hubs. However I always try to get a second opinion. Any ideas?

I've got a 97 tahoe LT that has 102,500 miles on it. When I engage the 4LO from either 2HI or 4HI there is a single loud clunking sound. It only happens when I go into 4LO, otherwise its quiet while driving in 4LO. Had a retired mechanic that I trust listen to it while I shift, he suggested that I take a look at the front hubs. However I always try to get a second opinion. Any ideas?


I wouldn't sweat it, I have a 98' does the same thing, Its normal to get a clunk going in an out of 4hi & 4lo.

My 2003 Z71 Tahoe does the same thing when shifted to 4LO. I wouldn't worry about.