: High pitched sound when hitting 60+ MPH?

07-11-10, 09:09 PM
Hi all, has anyone heard a high pitched sound when hitting a high speed? I only hear it when I go above 60 mph, I thought it was a window seal at first then noticed it sounded like it was coming from under the rear of the car, near the trunk. It stops when I drop below 60 again. Any ideas? Im a girl, dont know anything about car noises and want to be prepared when I take it in to the shop. I always get scammed. Thanks for any info!

07-11-10, 09:41 PM
Drop the rear seats down and take another ride with a "gear head" or "motor head" or maybe there is someone on the forum that lives near-by that could personally help you.
Good Luck

07-11-10, 09:45 PM
It is hard to diagnose a sound over the internet but it sounds like early differnential whine. If it is, it will tend to be louder at very light throttle and will often disappear when you ease off the throttle. A good way to check is to lower the rear seat trunk access door - this wll make differential whine much more noticeable.

PS: I type slower than Stepside.

07-11-10, 10:19 PM
Thats usually the police chasin you....:)

07-12-10, 07:49 PM
does it happen more or more loud when on gas above 60? does noise reduce when off gas above 60? Does the pitch (note) change the faster / slower you go above / below 60? if so it is very likely the diff whining... welcome to our world.

if it is ther eis little to do other than change out fluid with correct additive. You could go up to 75w-110 or 75w140 gear oil (regular is 75w-90). I have geard that the diff may quiet with new and heavier fluid to reduce whine. If it continues like mine, I am replacing mine on my terms before it lets me down.

Gary Wells
07-12-10, 08:48 PM
Well, there goes my "overhead jet" theory.
If that noise is coming from my '09 CTS-V, then I need to get my ears, my head, and my thought process examined. I might have it occasionally, but I am always or almost always on cruise control at about 73 or so, so I thought that it was something to do with certain stretches of freeway grooving. I appreciate the OP bringing it up, and the responses, as I really thought that it was tire noise. I will keep an eye on this and see what develops. Thanks, gang.

07-12-10, 11:23 PM
Thanks for all the help guys! The sound does get louder with acceleration but completely stops at 60. I googled a little bit and I think it might be a rear wheel bearing starting to go out. I have absolutely no idea what that is, but there is a recall for the rear axle pinion seal and when I take it in to get that replaced Im going to see about the bearing as well. I regret taking cooking in high school over auto class right about now.

07-13-10, 09:12 AM
The carrier bearing on the driveshaft on my car went bad and did that very thing. It would only come on at highway speed and go away when I would slow. It sounded like it was coming from under the center console. I had diff whine before (and diff replaced) so I knew it wasn't the same sound. If it is, your next problem is that GM decided to make the bearing un-serviceable, you have to get the whole shaft replaced for $$$$. Good luck.