My 06 crew cab has a 3.73 gear with a G80, and I think it is humming. I hear a humming noise at 80 and above and it sounds like its comming from the rear end. Any idea?

 

At 80 and above? How loud? Could be tire noise, axle bearing, pinion bearing, rear diff, etc. Might need to jack up the rear and run it in the air to listen with a stethoscope...

 

at 80 and above, it could be anything. Usually rear end noise you can hear in the 60-70 mph range.

 

My Yukon's and Zexel whine noticeably at 55-60. With a stock axle, whining at that high of a speed, relative to most stock trucks, could probably be a number of things. With as many problems as the Gov bombs have, I wouldn't be surprised though. Check and/or change your diff fluid and bearings, and also check your rear tire pressure.

 

it does not seem as bad now that I have new tires, I may replace the G80 soon anyway