mikenu_NJ

I have a 2008 A6 4.2. I've had it for about three years and it has 56k on it. About a month ago, I was driving it home, rounded the corner of my street and heard a nasty deep rumble from underneath. Same pulling into the driveway and the garage.

I woke up the next morning, got it up in the air and the front passenger axle failed - it popped out of the outer CV joint and the inner rubber was shredded and there was grease everywhere. Well I installed a new CV axle the next day and thought I was done. First test ride and the rumble was still there - I assumed it was AWD/Trans failure so I took it to a trans shop. He removed the trans, replaced the center differential (Torsen I think), gave me the old one and it did not move freely - the gears are all clobbered. Well the noise is 80-90% better but the normal binding sound is about 3x worse than stock. It's only present when you're making slow turns, worsens with the tightness of the turn and it's especially louder when I back up in a turn. I have chassis ears but haven't tested them yet. I'm going to lower the back seats and see if it's louder (with access to the trunk) to make sure it's really the rear.

I have options:

1. replace rear oil
2. replace with a used rear for about $400
3. take back to the guy (who offered to do 1 and 2) and check if there's a drivetrain alignment issue
4. live with it
5. take to the stealer and pay out the nose for diag and/or replace with a $4k rear.

I'm sure it's about 2 or 3 times louder than is should be so I'm wondering what you all have experienced.

Thanks for feedback.

Prospeeder

check the rear gear oil, See if its got a ton of metal in it. If there is you may want to replace the diff. If the diff caused the torsen to shred itself like that, It may do it again.