I replaced both rear wheel bearings about 3 months ago... and also changed diff fluid (Royal Purple 75W90).

Its a 99 2.8Q 5spd 145xxx miles, great condition and very well taken care of.

The car drove great for a while up until a week ago when that HUMMING noise is BACK!!

But this time around the humming is a bit louder, more constant and does not change/stop around corners...... what is going on????

 

Could be your front bearings?

 

I thought that as well because the front bearings haven't been changed yet, but really seems like its coming from the rear.
Even had my girlfriend and brother sit in the car and they both pin-pointed to the rear.....

Has anyone experienced the front wheel bearings fail and still sound like the noise is coming from the rear of the car...?

 

I know my right rear bearings went out twice. First time, it was because of poor service.

 

What brand of bearings did you purchase. It's a crock of **** but, not uncommon for aftermarket bearings to fail WAY to early. Replaced them 3 times on a previous car of mine, even with quality bearings. It's possible worn bushings and other components are assisting in the premature wear of them. Keep us updated !

 

The bigest key to long life with wheel bearing is proper torque when assembling. Air gun until the nut stops moving is not a torque spec!

 

Both left and right rears were replaced with *** bearings from ECS. And they were installed by an Audi/VW shop.

The control arms, bushings, subframe all seem intact with below average amount of wear for 145xxx miles which is why this is puzzling me..

 

There's your problem, you have *** bearings.

No but seriously, I would be leaning toward poor installation or worn suspension components causing this. Are the majority of your suspension components stock still? I'm not sure what the recommended service interval is for our cars as far as suspension goes, but nearly 150k seems like it might be close to maintenance time.

Just my two cents, good luck

 

Exactly my thoughts, however the shop confirmed everything was done to spec.

 

LOL, I figured the name would jinx this.

The front arms looked almost new when I bought the car about 1 year ago.
The rear needed axle/diff seals replaced but everything else seemed fine.
Had I known about the extensive maintenance problems I would've stayed away from buying the car.