First off, yes I searched. But, I didn't find anything like my issue.

So this just started yesterday. When in 4wd and when I let off the accelerator, I get this humming sound(not a grinding sound). As soon as I press the accelerator the noise stops. It sounds like its comming from under my feet/seat which leads me to think its my transfercase. Any ideas? Low fluid? I'll be able to check it out tomorrow.

I HAVE THE SAME ISSUE!!! IT BUGS THE **** OUT OF ME. lol let off at 30mph and it goes hummmmmmmmmmmmmzzzzzzzzzzzzzzzz and the noise lets up around 15-20mph

YES, thats when mine is doing it, at that speed...

hahah wierd. yea i have no clue what it is or why it is doing it. but my 4x4 works great.

I got the same exact humming noise but my has some vibration along with it also comes back at higher speeds 65mph and higher!!!! I would love to be able to figure this out!!!

I think my noise is coming from the back seat or cargo area though..

Murdoc and Green - check your t-case chain and make sure it's tight. Also check your t-case fluid level/quality. Check your u-joints front and rear just to make sure those are good too.

bambam - rear drive shaft u-joints need to be replaced.

Ok, so if my t-case chain is loose can it be tightened? Or do I replace it?

You can tighten it by adjusting the links, but you need to be real specific on the adjustment. Too little and you keep your current problem. Too much and you rick the chain "hopping" when you go to engage 4hi/lo and then you're just stuck in neutral. I'd go ahead and get a new one if it's loose when you look at it.

mine made the same stupid noise when i let of the gas, then i did a SYE install to find out my t-case chain was rubbing on the bottom of the t-case cause it was streched out to far. replaced the chain along with the SYE install and WALLA!!! no more noise!

Thanks I had a feeling it was something with the drive shaft. considering doing the iron rock sye kit with a front drive shaft. i dont like that my stock slip joint has play in it.