PretzelActual

A little less than 2 years ago i picked up a manual 2002 audi tt quattro roadster and its been a great first car but from the day that i got it has always had a lot of road noise from the rear and i have just put up with it. However, it has been getting worse recently and is driving me crazy. It makes 2 sounds, one that is like a combination of diff whine and bad wheel bearings, it increases with speed and when i'm cruising between 55-70 mph its almost as loud as a jeep with big off-road tires. The second sound occurs at low speeds around 5-10 mph and it is this terrible groan/grrrr noise that only happens when im not on the throttle, it also happens at low speed 90 degree turns around 10-15 mph but is not as loud as the slower speed noise. All these sounds occur every single time I drive it and it doesn't matter if its in gear or out of gear.

I've checked the bearings, cv axles, gotten new tires and an alignment (the original tires had developed some flat spots on the inside of the rear tires), nothing has fixed the noises. Yesterday i finally pulled the haldex fuse and boom, no noise, no whine or groan and it drives perfect. I put the fuse back in and its right back to how it was, so at least i know its something to do with the haldex unit but that's not really too much of a relief as a new haldex unit is just too expensive for me and the guy i got the car from said that he had recently changed the haldex fluid and filter before i bought it, he even gave us an extra tube of haldex fluid and a filter that he had for it.

I really don't know what to do because i cant afford a new haldex unit, I guess I'll change the fluid and filter this weekend but i don't really think that's gonna fix much as I have a sneaking suspicion that the guy I got it from had the same problem and when changing the fluid did not fix it he decided just to sell it to someone who didn't know that there was an issue.

Anyone have advice/suggestions? Thanks in advance!

oldroller

Capture the fluid from the Haldex and the differential in separate containers, and examine the contents. It should give
you an indication of which component is causing the noise. But as you said it was completely quiet with the fuse pulled,
I would warrant the Haldex is cooked.