I get this moan/groan from the rear when backing up or driving off. This is more prevalent during the morning at first drive off. I also notice it after the car has been at rest for a while.

Does anyone else have this same problem on '07 Tahoe? What is it and how do you fix it?

 

I had a similar issue with my 07 too. I noticed a moaning type sound mainly when driving around 50 mph and coasting. I took it to the dealer and they replaced the pinion seals and that solved my problem. Now mine had about 98k on it but was still covered under the 100k warranty.

 

Mine only last for a few feet of driving then it goes away.

 

Disc brakes on the rear axle?
If yes, could it be caused by the overnight rust on the rotors being wiped off after a few rotations?

Those pinion seals must have pretty stiff to make groans and moans!!!
Maybe they replaced the pinion bearings too?
If those went bad it would moan and groan.

 

yea, it sounds like disk brakes pad on the rear rotors. give this a try, hold the pedal lightly as you shift into gear and see if it makes that groan, forward & reverse.