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dannslc
02-09-2008, 12:24 PM
I recently started to hear a drone or a humming noise coming the rear end of the car. It is loudest around 35 to 50mph. I can only hear it with the windows up and radio off. The car has 96000 miles, I am worried this could be something to do with the differential as it is right in the area where the sound is coming from. What else could be the issue here?

P3RryaudiA4
02-09-2008, 12:27 PM
wheel bearing, if it gets louder around turns and when u accelerate

dannslc
02-09-2008, 12:33 PM
Nope doesn't change around turns. I don't hear the noise until I get up to 30mph and it doesn't get any louder as I accelerate.

P3RryaudiA4
02-09-2008, 12:36 PM
u manual ?

dannslc
02-09-2008, 12:45 PM
yeah

P3RryaudiA4
02-09-2008, 12:49 PM
also r u quattro or front ? and r u absolutly posative its in the rear over the axles and not in the middle u need to depict this is a transmisson noise or a differintal noise make sure tho, noises are a bitch have someone drive around in ur trunk thats how i'd find out wear its coming from lol sound funny but its tru also when u hear it what gear r u in and does it change when u shift all of this might be useless if u know its not ur transmison but figured i ask

dannslc
02-09-2008, 01:10 PM
Yes i'm quattro. I drove around for a good long time trying to determine where the noise was coming from. I am 95 percent sure its coming from the rear end. I hear it best in 3rd and 4th because that is when it is very quiet, I am sure it is doing it in second but cant here it as well. Pretty sure its not my tranny, the noise is definenlty in the back.

P3RryaudiA4
02-09-2008, 01:19 PM
hav eu ever changes the rear diff fluid ? i mean u said u got alot of miles right it could be something as simple as gear clash or u could have bigger problem

dannslc
02-09-2008, 01:25 PM
Yeah that was my next question. I have been meaning to change the diff fluid for some time now. I will prolly take care of that this week.

P3RryaudiA4
02-09-2008, 01:41 PM
well for now thats all i can say change it then take it from ther let me kno how it goes hope ur prob goes away

quattro_mds
02-11-2008, 07:14 AM
I had the same symptoms! Turned out both rear wheel bearings were on there way out.

98a4
02-11-2008, 09:04 AM
Its a wheel bearing.
Do that first, don't get the guy all worked up aobut his dif.
Flush is a good idea still

maxspeed
02-11-2008, 09:11 AM
im havin the same symptoms, im pretty sure its wheel bearings based on whem they went out in my moms car it was the same, just not as loud or speed depenedent.

dannslc
02-13-2008, 06:23 AM
Thanks on the not getting me worked about the diff. I was getting worried. I have been reading a lot of posts and am leaning toward a wheel bearing as well. I also have not gotten around to changing the fluid yet, but will soon. Hey P3R thanks for the help though.

dannslc
02-13-2008, 06:26 AM
My biggest question is about the speed dependancy. When my front wheel bearing was going, it was all about the speed I was traveling at. The noise would would always change.

ModifiedA4
02-13-2008, 08:17 AM
checking the diff seals is worth it, just peer under each wheel well and look at each drive axle. when the diff seals go, it sprays fluid all over. if that area is 'wet' then its the diff.

easy to check. one of mine went at 30K.

quattro_mds
02-13-2008, 08:30 AM
in addition, if it turns out to be a rear wheel bearing. If you can get both of them replaced at the same time. Since you will need an alignment when one is replaced, you might as well get both of them done. Plus the other one is close to dying anyways, it may last maybe 5 miles, 50 miles or 5000 miles who knows.

Siena
02-14-2008, 01:23 AM
My car hummed like mad when I first got her.

Replaced both rear wheel bearings, all quiet now. You can do the job without a press too.

Both sides took me just under 2 hours on my driveway.

dannslc
02-14-2008, 09:32 AM
Thanks for the help guys. After driving around for the last couple days I am sure that the problem is a wheel bearing. I am going to replace them soon. I have been looking for a diy, but can only find diy's for front bearings and s4 rear bearings. Does anybody have a diy link?

98a4
02-14-2008, 10:04 AM
AudiDIY.com should have one

dannslc
02-14-2008, 10:18 AM
Nope they only have a diy for the front bearings.

98a4
02-14-2008, 10:38 AM
http://www.audiworld.com/tech/wheel.html

35 second search

dannslc
02-14-2008, 10:48 PM
Thanks. I totally looked on there too. I missed it I guess. We all have those retarded moments ya know.

nyca4tq
03-16-2008, 01:26 PM
Id say wheel bearings, just had mine done last week, I kinda help them along by hitting a guard rail or two in snow and dodging deer...dont ask...long story.

Jayh922
10-16-2008, 10:13 AM
my back two wheels are making a humming type sound also. Should i replace the bearings? How much would it cost for labor?

AudiRacerS4
10-16-2008, 10:23 AM
my back two wheels are making a humming type sound also. Should i replace the bearings? How much would it cost for labor?

yeah most likely its a wheel bearing, jack the car up and spin the back wheels if you hear a humming/grinding noise its the bearing. the bearing is about $60 bucks and labor should be around $200 since the rear spindle has to be removed and the old bearing has to be pressed out and the new one pressed in [wrench]

offroader1006
10-16-2008, 11:44 AM
my back two wheels are making a humming type sound also. Should i replace the bearings? How much would it cost for labor?

its just as feared.

you have a small acapella group forming in the rear of your car.