noise in 4wd

I have a 99 Z71 and the other day i switched to 4 hi while on the ice. worked great but when i got up to about 35 i could hear a whine coming from the front driveline. does anybody know if this is common for these trucks? i just had tranny, transfer case, and diff fluids changed. never had a 4x4 that wasnt mor than 15 years old, and im kinda lost with this one

There should be a little whine but it shouldn't stand out. My 96 whines on the highway in 4X4.

that'll work, you have to have the radio off to hear it so i wont worry about it then, thanks a lot