Lately my car has been making a sort of high pitched whining or whirling sound. (sort of sounds like Wweeeeeeeuuurrrrrrrrrrerrrr ) The pitch gets lower as the car slows down, and higher as I speed up. It is sort of intermittent and does not happen consistently. I usually notice it when I am slowing down and have the car in neutral. I think it is happening in and out of gear at low speeds, but it's hard to hear because of my exhaust. There is no clunking or anything like that. I cannot hear it at medium to high speeds and the car runs great overall.

It's been 2-2.5 years since I've changed my differential fluid (Mobil 1 syn 75-90w), and about 2 since I've changed the transmission fluid (GM synchromesh). Do you think changing them will help? I am already planning on it soon so I'm just curious. Could my differential possible be going? I have autocrossed the car 7-8 times w/ 5-6K RPM clutch dump launches (I know, bad!), although that was a 2-3 years ago and has mostly been daily driven since then. Also, I have an upgraded clutch, not a full blown racing clutch just a heavy duty pressure plate w/ oem disc.

 

if all that use (or...abuse ) was on that differential fluid, I hope whining is the least of your problems.

Definately change it out and report back. Of course...check to see if (or in your case how much) metal shavings are floating around.

How many miles on it?

 

The car has 60K miles, while it was autocrossed I changed it at least annually. I did change it after I stopped autocrossing it, but it's been maybe 15K / 2-2.5 years since the last change like I said. It started making the whining noise way after I stopped autocrossing and was using it mainly as a daily driver, 20 miles city driving a day. I still drive it pretty hard on occasion though. Going to pick up some Mobil syn. 75-90w and change it tonight. If that doesn't make it any better, I'll change the transmission fluid too.

 

Also, what's the best fluid to dampen the sound? Would straight 90w do a better job than 75-90w?

 

Mind over matter, my friend. 75-90W will do fine.

 

Well, I changed the differential oil with Mobil 1 75w90 tonight. The previous fluid (LE-607) looked black and was extremely thick, even after driving it for 15 minutes or so to warm it up. It also seemed like there wasn't very much in there. I completely emptied out the old oil into a drain pan (no metal chunks or anything, but lots of metallic looking dust and gunk on the drain bolt), filled the differential up with almost the whole quart, lowered the car to let the excess oil drain out, and wound up with less than 900 ml when I poured it back into the bottle. Does gear oil burn off and thicken up after a while?

I went for a drive after and the car felt MUCH better. This might all be in my head but it seems like it revved easier, shifted smoother, vibrated less, and just felt better overall especially in the upper RPMs when VTEC kicked in. There was less noticeable noise at low speeds and while turning, although I could BARELY hear a slight whine out of it occasionally, but I think my car has always sounded like that. Also, I quit coasting around like a dumbass and started leaving the car in the appropriate gear, which is safer and seems to cut the noise out almost completely.

 

Good to here you have saved your self a good bit of money
If you here a slight whine at times this is normal, even the stock 4.10 will have a slight whine to it.

 

i was going to say that maybe you had gotten REALLY REALLY drunk and installed a turbo that you didn't remember...

 

Nope, but that would have been sweet! (as long as it was installed OK ).