Whistling noise

**Lumpo** · 09-02-2009, 05:19 PM

I got a 1995 Chevy Suburban and between 45 and 65 mph im getting a whistling/howling noise and it kinda sounds like when you blow on top of a bottle. When im hearing the noise and switch to neutral the noise goes away so its only when im in drive. Its got new U-joints, tranny was redone, new throttle body gasket and i tried taking the front driveshaft out with no change in the sound. To me it kinda sounds like its in the middle of the truck but im running out of ideas. Any help would be appreciated.

**unplugged** · 09-02-2009, 06:38 PM

Are the windows up when you are testing? Burbs are known for a buffeting sound when the rear passenger windows are down.

As far as pinpointing a noise, I like to use vacuum tubing taped in different locations to form a crude stethoscope.

You could also try putting it up on a lift and running the vehicle to see if you can duplicate the sound and walk around/under it to isolate the location of the noise.

**Lumpo** · 09-03-2009, 11:28 AM

Yes windows are up when im testing. I have full access to a rack but havent tried to duplicate the noise while on it. Might have to try it.

**Lumpo** · 09-03-2009, 12:38 PM

Had truck on rack spinning the tires 45 to 65 mph and i couldnt make the truck make the noise. So it needs the load of the truck to make the noise. What you guys think.

**unplugged** · 09-03-2009, 10:53 PM

Sounds more like it might be a wind driven noise. Where is rent a wind tunnel when you need one?
Try and isolate it above or below the burb and work from there. Look for anything loose like the roof rack or the cowling below the windshield etc.

**Lumpo** · 09-04-2009, 04:21 PM

Its not wind noise because if i put it in neutral while its making the noise and coast the noise goes away.

**Crawdaddy** · 09-04-2009, 04:31 PM

So if you just coast down with the transmission still in drive it still makes the whistling noise? If so, the motor could probably be safely taken out of the suspicion list. It could possibly be the rear differential. If it is the differential, it would be that the gears are whining and could possibly be going out soon...not good. For that matter, transmission issues aren't good either.