When cruising in the car, there is a loud whining noise coming from the rear - like a woo-woo sound. It only happens when I take my foot off the gas - if I touch the gas at all it goes away until i let off again. The fluid in the differential was changed recently. Does anyone know what could be causing this noise - I don't want to ruin the rear end or anything by driving it. Any help would be greatly appreciated.

 

It's already bad, you need a new set of gears installed, or another axle.

 

Is there anything else that could be making the noise other than bad gears?

 

Are they stock? My Richmond gears have whined since they where installed years ago, when letting off the gas or light throttle cruising with no ill effects.

 

Have you checked the fluid level yet?

Also, did you put in the GM additive? I have had a rear or two whine without the additive and go dead quiet with it. :shrug:

 

I'm no expert (as most people know I keep bugging real guys with my own questions every 3 days),

but if it is high-pitched sound, it could be a bearing. A common thing is that when rear end is build, pinion bearing is not fully seated (or something like that), so after a while it looses its preload and starts making that type of noise.

I don't know if you can destroy the bearing itself, but if it gets loose enough, it can make your pinion move. Then you will destroy a lot more.

And like other guys said, aftermarket gears by default are noticably more noisy than stock GM.

 

I am not sure about woo-woo noise, but if you get a whine when you let the gas off it often indicates the pinion bearing. It might be worn or the pre load is not right. If the whine goes away with very light throttle, the bearing is probably not wasted.

 

My '97 Astro van is making the same noise on deceleration and around corners. It needs new spyder gears. I've also been driving it like this for the better part of a year.

 

Generally, it's the pinion bearing.

 

when I changed my pinion seal I didn't tighten the nut all the way and all was good until I let of the gas and it sounder like a jet engine whining down I tighten down the nut and it disappeared

 

Huntingwood, check your pinion nut. I just had that problem with my car. My car has a manual trans so easy for me to put it in neutral to kill the noise. Then I rean how bad it could b and I had it towed home from work, didn't wanna break it. Apparently my pinion nut had backed off and diff started whining. I replaced the seal, put sealnt on inside of pinion yoke, lok tite on nut and tightened as much as I could. Torque should b 125-150 '-lbs though.
Hope yours is as cheap as mine

 

5 years later, he's probably gotten it fixed by now. Nonetheless, good information.

 

Oops, thought I was helpin em out. Replying from my phone, found the thread through google and assumed it was recent.

 

LOL I've done it before too.