4x4 Noise?

[Murf]

Have 15,000 miles on GMC D/A. Today while towing a 9,000lb trailer I ran into some snow on the road on I-70 around Vail, CO. I put it in 4wd and around the 2,200rpm mark while in T/H I would get a whineing sound coming from what felt to be around the transfer case. It wasan't debilatating but somewhat annoying. As I have hardly used the 4x4 yet and I think never at the 50-65 mph range I was wondering if this was normal? It didn't shake or anything like that and it only made a noise (like a whineing)
as I would accelerate. No noise in 2wd. Did not get to try it out of T/H as it was a bit nip and tuck out there with the big rigs etc running off the road. Any ideas, suggestions for action?

Thanks - Murf

[mark45678]

I put about 50 mile on my new truck this weekend... I found there was alot of front axal noise and some transfer case noise... It started getting quieter the more I drove it? I am going to put 20 more miles on it, if it doesnt ware in the dealer will be looking at it! I think theres a little break in going on! Change your tcase fluid my 2001 had lots of metal in the fluid!