Blue70

OK
I have a howl coming from the rear of my car, it sounds like a big 4x4 is riding over my right shoulder.
I thought maybe it was my tires (BFG Radial TA's) because it didn't sound like gears, but today I took a sharp left turn and the noise went away while I was turning, but came back when I straightened out. The noise is still there if I make a sharp right turn.
Where should I be looking? :crazy:

JB

Sounds like your pumpkin. When was the last time you changed out your differential fluid and put in some fresh posi additive?

JB


[Modified by JB, 4:29 PM 3/23/2004]

GTR1999

Howl could be coming from differential pinion bearings,was the pinion seal replaced recently? Could also be rear bearings or side yokes grinding.
What I would do is get the rear up on jack stands and look underneath for any signs of metal scraping around the diffhousing and yokes.
Remove the 1/2 shafts and check the joints for looseness and rust around the caps. Then check the yoke play in/out of the differential, if you have more then .050" then you might have a problem there. How old are the gears,they might just be worn out too. You have to start looking but be aware if the rear suspension id original or has been worked on by Bubba you may be getting into big $$ land. If you can do the work yourself then you can could the cost down by a lot.
Good luck and ask questions when you start diggin in.
Gary

Blue70

I've only had the car 2 mths...I have never changed the diff fluid.
Think that could be it? What weight gear oil should I use?

red79c3

I had the same kinda noise a couple of years ago. The pins that hold my yokes in place, one borke because of age and my back tire started to drop in.

GTR1999

Usually the oil and the posi additive change will help if get a knocking going around a corner, It feels like someone hitting the rear with a hammer. Is this what you have? It's worth a try, you'll have to suck out the old oil-use a pump it's much easier, and add 2 bottles of GM posi additive,fill the diff to the fill hole bottom with 90 wt gear oil. Jack the car up and remove the right tire use a long extension to reach in and remove the plug. Try to get the rear housing as level as you can when filling.
Gary

Blue70

There is no grinding, clunking, poping.
It's just a howl, like tire noise when riding in a truck.
It builds with speed, and will only go away while taking a sharp right during "spirited" driving. During "normal" driving the noise is still there taking a right hand turn.

GTR1999

Can you swap out the tires with some good used ones to be sure,although I'd still be looking in the differential/suspension.
Gary


[Modified by gtr1999, 5:59 PM 3/23/2004]

mark79,80

Had a similar noise with my 1979 corvette. Howl became louder when
the car warmed up and the higher the speed.
Changed the rear end fluid and the noise was the same.
Had a local shop rebuild the rear end including changing the ring and pinion.
Even though there was no visible wear on the ring and pinion they
recommended replacing it as they said the way the gears mesh could
cause the noise. They also changed the clutch pack and all the u joints.
Not sure what in the rear end was causing the noise,
but after the rebuild the noise was gone.


[Modified by mark79,80, 5:04 PM 3/23/2004]

Vette-4-Life

I had a very similiar howl in my car. When i let off the gas with the car in gear it would change from a howling noise to a high pitched whine. Had the diff. rebuilt and the howling was gone, that noise cost me $1800 to eliminate.

Blue70

The noise is the same if I am on the gas or off the gas, and it's not a whine, that's why I was originally leaning away from the gears.

MN-Brent

I had a similar constant noise that you describe with my '98 ZR2 Blazer. It turned out to be the driveshaft rear U-joint (only 75K miles too).

Also had a noise in my 82s rear end upon turning to the right, I got a squeek squeek noise. I replaced halfshaft U-joints and added new gear oil and posi lube and that did the trick.

For your vette, I would start with the cheapest fixes first and then move up to expensive:

1-check rear end fluid level. It should be up to the fill hole. You might try to just replace fluid with 80W90 gear oil and GM Posi additive from the dealer. $15

2- Replace your driveshaft and halfshaft U-joints. You'll know if one was bad as you will find a dry or damaged needle bearing if it is making noise all the time. Once halfshafts are off, you can try to check your trailing arm spindle bearings for smoothness and check you differential yokes for end play. $75 to $100 depending on source. I recommend Brute Force non greasables as an alternative to Spicers.

4- Replace rear bearings in trailing arm spindle assembly. $$$$$

5- Rebuild rear end differential assembly. $$$$

Good luck...


[Modified by MN-Brent, 7:48 PM 3/23/2004]