Do I Have Bad Driveline Bearings?

[Johnshan]

I have a 1999 Z71 with the 5.3L and I have a loud hum from the truck. It has 136K miles.

 

When I turn right it goes away. Sounds like a bad right wheel bearing right? Not so sure-

 

Heres the kicker, it also only makes noise when I do not apply any throttle. If I touch the throttle it goes away, let off and the humming/roar is right back.

 

It feels like its coming from under the console.

 

Any ideas? Thanks, this is driving me nuts.

[Alljackedup408]

could be a pinion bearing

[Zembonez]

could be a pinion bearing

Possibly. Pretty hard call. It might be in the front driveshaft or noise coming from the transfer case. Are you certain the transfer case if full of fluid?

[Alljackedup408]

would it do it in drive if it was just idling? if so.. put it up on jack stands with some one in it... and get under with a scope or prybar... and listen to the different components.. if you hear a roar outta sumthing... chances are thats it.