A few days ago i noticed there there was a slight hum/whine coming from beneath the floorboard upon deceleration and didnt think too much of it but checked my fluids, nothing seemed to out of the ordinary so i didnt think to much about it. well the past couple of days i have kept my stereo off and have just been listening and sure enough the past couple of day it has gotten worse. Its loud around 45-50 and 20-30mph. concerned about the front driveshaft assembly i pulled my front drive shaft before heading home to see if it would stop. STILL THERE!!! So i got to messing with it on the way home and noticed that if i give it just enough gas to take away from the drag it would go away. So then i would shift to neutral to see if it would still do it and nothing in neutral. as i would shift in and out of neutral it you come and go. Any suggestions this is my daily driver/work vehicle so i need to figure something out fast.

 

I've got the same thing! Driving me nuts as well, and I've no clue if it's a vacuum leak, or what?

 

What's the transfer case fluid look like?