newbie here!

[Scott0o0o0]

Just a traveling dude that happens to be working in Texas for the next couple of years. Who knows where I will be next!
Actually got on here to get some input on my truck. I have bought my first Chevy 4X4, 2007 Crew. I have about 30000 miles on it now.
Question is, I sometimes lock it in 4H to do a little driving in it, just straight driving around 45-55 mph for a couple of miles or so. Then I may lock it in 4L and creep a little in a parking lot. Have only done this maybe 3 times since I bought it. The last time I did it, there was a lot of grinding sounding noise coming from the front end in 4H when I would make a regular turn from one road on to another. When I lock it in 4L and turn the wheel to turn, the noise is there as well and it just stops on its own without pressing the brake. It also did this in 4H. It makes a rather loud noise when disengaging from 4L to 2H.
I am going to take it to the dealership but don't want them blowing smoke up my ass.
Any ideas??