Allright, I've just joined the 10-bolt rear end sucks club. I have a 01 Z28 (A4). About a month ago I noticed a "wa wa wa wa" sound from the back of the car once I get outta first gear. Thought it might be tire noise. Needed brake work anyway, so I took it in this week for new pads, rotors, caliper back there. Noise is still there. Took it a chain to get rear diff service. Guy drove it around first and says the service won't help, there something wrong in the rear end. He said they spun the axel on rack and heard a clicking noise in the gear box.

Now this is my only car, my daily commuter. I don't race, don't drive crazy, etc. It's got a shade under 62k miles, so this is really disappointing. I don't have 1250 for a rebuild, or 2500 for a 12 bolt upgrade. So basically, my question is how long do I have until I'm driving down the road and the gears tear themselves apart? I can live the sound, but I don't want to be stranded on the interstate one day.

 

Sorry to hear your troubles, but this could be anything..

What gear was he in when he spun the axle, how did he do that, at the tires or the driveshaft somehow?
What did the clicking sound like?
Was it just the slack being brought up through the drivtrain?
How fast did he spin it? Probably nowhere near fast enough to hear the gears...

Sorry man, but his guy sounds like an idiot or he didn't give you all the details...

The way you describe this "wa wa wa wa" noice makes it sound repetative, does it increase/decrease with RPM or road speed, these are different so it may take some delicate listening. But the easy way to telt is to get to a speed that it is making the noise maintain that speed and manually change/hold gears to increase/decrease RPM and listen to "wa wa wa wa" sound. If it increases and decreases with RPM I would then worry about the tranny. If it stays that same, go back and get a gear service done, and you might mant to find a different shop. I am not saying that it is definitly the rear if it changes with road speed, but there are less chances of it being the tranny...

Good luck with it...

 

Unless he was refering to the carrier/differential as the "gear box", in that case take it somewhere to have it serviced and most of the time they will check it out too. Again try another shop... or find someone in you area specializing in drivetrain or rear setup, ask you local rares for recommendations.

 

Thanks for the response.

I didn't see him spin axel or driveshaft, nor did I hear it first hand (was sitting in the waiting area when he walked back in).

The noise itself changes in time with the speed of the car (not necessarily the RPMS). To clarify, the noise is not present in reverse, or first gear. Once I get to second though, it starts making the noise. The frequency in duration is tied to the speed at which I'm travelling. So if I let go of the throttle and coast, the sound slows down as the car slows down, irrespective of the actual RPMS. Definately coming from the back of the car, sounds almost like bent rim, but the car's not shaking and the tires seem fine.

I'll try to trackdown a rear-end specialist in town. I went to a midas shop (that was the chain) and they didn't know of any. Thanks