Noise comming from rear end

going down the road you can hear this loud tone comming from the rear end. When you let off the gas it gets really loud for like a second then goes away, then when you get on the gas it starts doing it again. Anyone know what this could be? My friend that works at the dealership where I bought it at said that he has had numerous complaints about it with other Fbodys, and that it is just something in the rear end and I am going to have to get used to it/ignore it. Does anyone know what it is, and do you also experience it. He said it was because of the design of the car or something. I figured if I took it to get it all lubed up and stuff it would go away, but it didnt. thanks for the input!

What does the noise sound like... Do you have the rear cargo space, cover down.. what im wondering is with my car without that cover over the cargo space i could here the fuel pump whine... and u can hear it when i drive (at least b4 i got my exhaust now i cant hear over that :))

hope that helps

i have the cargo area. It just sounds like a constant tone, like on a cell phone, if you press and hold a button, a tone like that (well kinda, you get the idea) My system drows out the noise but if you got someone riding with you and you are trying to talk, its annoying.

sounds like your gears. my 410s whine like that. do you have after market gears

yeah the guy told me it was the gears. I have the stock gears though. What kind are they anyways? I have the 99 3.8L Automatic. He said there was nothing i could do about it. Also, if I was to upgrade my gears, what kind whould I want to get, and what performance difference would it create?

could be the fluid in your differential that is low. check it

i'd get 342 373 or 410s. performance varies. i have heard that GM automotive are the best and quitest

No gear set is loud or whines if the proper lash is set. You don't have to live with noise to run 4.10's.

Now, as for limited slip differentials, those, depending on what type you get can make noise. I believe spring-gear types are the loudest.
A Clutch type should be silent.

My gears whine because they are going out. It's a '98 with high miles. Although, gear whine is constant, and pitch/volume changes with speed.

Not sure what the noise could be, i've never heard anything like that before, but if you get aftermarket gears, I'd get the 3.42's or the 3.73's. i think 4.10's are a little too much. But it also depends on what kinda mods you have done and what you have done. If your gonna keep it stock, then i'd say 3.42's. You'll get a gain of no more than 1-2 tenths at the track.

Good Luck man

Sounds like the gears need to be replaced. I have a set of 3.42s i will sell you for $60 shipped.

Ok I was going down the highway today and this is what the deal is. The noise only comes at 1900 RPMs (crusing speed), and only if I am going over 50 MPH. Does that help any, or do I need to just get new rearend gears?

rear end should be fine, but yeah that sounds like gears. They whine from 1 MPH for me due to how bad mine are. But yours will whine at any speed, you may only here it when on the highway. At higher speeds road noise is probably masking the whine. But I'll bet its gears.

How long was it since you flushed and refilled the differential???



















...yeah...me too!!!

Originally posted by Bliggida
How long was it since you flushed and refilled the differential???


Ha.....told you so...

Check the fluid.

Its suprising sometimes what a mechanic can overlook. But I have an excuse.

I'm maintaining an entire fleet.

You'll need to check the differential fluid...flush and refill religously with a posi unit in there.

I'm pretty sure I am going to go ahead an install a drain plug.

I just got the car almost a month ago. You think it would be covered to get it flushed and all on the warranty I bought. It was for the Engine and drivetrain. If not, how much to get someone to do it? I dont know how to do it, so I would pay someone else, and not take the risk of messin it up. thanks for the help guys, its appreciated!

...differential is part of the drivetrain.

If you wanted to do it yourself, I could walk you throught it, with pictures.

Originally posted by Bliggida
[BIf you wanted to do it yourself, I could walk you throught it, with pictures. [/B]


I love seeing this kind of stuff.....much props to you Bliggida.:bow: :metal:

oh yeah dude, I painted the differential cover. Color keyed to the exterior! Better than having a limited slip!!!
AIM me for the pics.

:D