Noise coming from transfer case when accelerating?

[gonefishing]

The other day I engaged 4HI just to make sure everything was good to go since winter is on it's way. I don't use it much during the summer. I heard a noise that I haven't noticed before. The noise was only audible when I accelerated. Let off the pedal and I couldn't hear it. Give it some gas and it came back. I can replicate it every time in either auto or 4HI. Go back to 2HI and it's gone. The sound is coming from underneath the vehicle. I'm assuming its the transfer case since it only appears when it's engaged. It's a faint hum (not grinding or anything).

Anyone else every experiece anything like this? For all I know it's always been like this but just noticed it recently. Had to turn the fan and radio off to really hear it.

Thanks

 

[Killer223]

just the front driveline spinning, might check the u-joints and the dbl cardon joint as well.

 

[andyd]

Check lube levels in front end and T case

 

[Lyman]

Sounds like a typical front drive shaft issue.

 

[gonefishing]

Thank you everyone for the feedback. I'm due for a T-case and front axle lube change. Hope to do that next week. Will also inspect front driveshaft.