Calif_Kid

I'm guessing that the whine is from the Aprikol rear diff mount. I have one on my car, and I get a similar whine at highway speeds. Originally, I had the blue (street) insert, but it got torn due to track use, so I now use the red race insert, but I got the whine with both types of inserts. If you do searches (Audiworld, QuattroWorld, or Audizine) on the Aprikol rear diff mount, I think that you will find that quite a few people have the whine/noise with the Aprikol diff mount. If you have a stock rear diff mount, you could always swap it in pretty easily and see if the whine goes away. - Jim

mikk23

Hmm...all good points. I didn't install that wheel bearing myself...but I'm pretty confident in the mechanic that did it and I think I've only put about 7000 miles on it since then. No bodies perfect of course but for now I suspect something else. I know the Aprikol mounts can be noisey...but drowning out the stereo whine? At all other speeds I can here a soft whine that I would expect...but at 58 or so mph out of no where...its a howl...almost like being in a lifted truck with mud tires on the freeway. Just not quite that low or rough...but similar volume. And it seems to get worse almost like something is heating up until about 20 minutes on the freeway and it peaks and stays that way. I'd try the stock mount but mine was tore up bad and went straight to the garbage when I removed it. Was/is your aprikol mount this loud? I'm using the blue type as I dont hit the track but once or twice a year. I'm going to check the other forums like you mentioned for posts on that mount. Are there any other mounts out there that will do the same thing and not make me yell to hold a convo with the person in my passenger seat on the freeway? Lol.

And if its not one thing...its another...blew a flat on the way to work this morning *sigh* Tirerack here we come...


Thanks for all your input...Keep it coming!

Calif_Kid

I usually just hear the whine at freeway speeds. I haven't noticed any change in the noise for when the car is cold versus hot. I'm not sure about noises from other types of aftermarket mounts, but if you search, you should be able to find more info. As many people have replaced the rear diff mount, I'm betting that if you posted something for the area that you are located, that someone will have a spare stock mount, and it should be pretty inexpensive. Main thing, is to give the stock one a try, and I bet your whine will go away. Good luck!! - Jim

edoushe

is it a whining or humming? i had a whining noise, same location, same sequence went away/got quieter when let off throttle, im about to change my FUEL FILTER, which i talked to a couple people and well anyhow ill let you know tomorrow if that fixed it.

mikk23

How did the fuel filter work out for you? I need to replace that regardless of any noise I'm hearing...lol. Just did it on my wifes A6...all sorts of crap fell out of it. Definately need to change the one in my S4 after seeing that. I would consider what I am hearing a high pitch whine thats definately speed related.

Thanks for all the input Jim...I'll start looking around for a stock mount I guess...give that a shot. Any S4 owners with a stock mount in semi decent shape in the Southern AL northern FL area?

s4ddriverr

I can tell you 100% for sure its your rear diff mount because you said it goes away or changes sound when you let off the gas, my car started doing the same thing when I modified my diff mount.

ExpStang

Its the rear diff itself. Common problem have your rear diff rebuilt or locate a good used one.

AndrewF1

I had the same problem and it was my front diff which is part of the trans. I hope for your wallet's sake that isn't it. Somewhere in your driveline you have a toasted bearing. Check your fluid levels in your rear diff, torsion, and trans, if one of them is missing all the fluid you may have found the problem.

Andy

Holographic77

I'm actually experiencing this exact same problem now. Installed the Apikol diff mount (blue), and changed out all other mounts. Very loud whining sound between 60-70mph, which can change in sound depending on throttle. I never had this whine present previously, as far as I could tell with the old oem mount.
Is it just a matter of the stiffer poly mount transmitting sound, or is there an actual problem with the diff/bearing?