Hi there, I have had very few issues with my '06 6-spd A4 2.0T to date other then pretty routine stuff. I have about 170k now.. I recently started to hear a noise like a whirring or tire noise on the highway a few days ago, (i had also noticed it was tracking weirdly on the road, not able to maintain the lane that well). I thought (from my research) it might be wheel bearing. I took it to my guy (the head guy is on vaca until tomorrow) but the mechanic there said it was not wheel bearing and it looks like the front differential needs to be replaced! Is this common on higher mileage a4's?
How much might I expect to pay for this? All i was told is its expensive.

Do I have to go to dealer to get done? (i ask b/c I called another guy nearby said he wouldn't do this job saying the dealer would have to).
Im scared to drive it! Its making noise, I think for now, its ok to dirve but what can i expect?
Could it break suddenly?

Any advice is appreciated im feeling lost right now and wondering if i should keep my typically trusty girl. Plus, im just a few months to finally paying the darn thing off lol... go figure. thanks.

 

I would get second opinion? Sounds like a wheel bearing to me...

 

I have yet to hear of the front differential going bad. I agree get a second opinion.

 

They can go bad if there may be a neglected leak due to old seals. This is easy to see with a flashlight in the engine bay. The transmission fluid will have leaked out, coating the axle flange and the inner CV housing, making it look wet all the time. If they are indeed wet you need to nip this in the bud since things might've already progressed. In the Tiptronic Automatic and 6 speed transmission, the front differential shares the transmission fluid. You don't want things to advance to the transmission. For CVT transmissions, the differential has it's own fluid reservoir.

Bad bearings are easy to spot since they often allow too much lateral movement of the wheel. To do this the car should be jacked up and you take the tire by 3 and 9 oclock/6 and 12 o'clock ( do both to make sure it's not steering play ) and wiggle. The free play should be very apparent if they are worn.

Both can be serviced at a competent Audi/Euro mechanic.