1982 corvette differential noise
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1982 corvette differential noise
So I have a 1982 corvette that Just passed 70 thousand miles. But I’ve been having this noise for alittle bit of time. It’s this vibration/low humming noise coming from my rear end. I also will note that at low gears and at high rpm the noise is non existent but at low gears (especially when accelerating) do I hear that hum/vibration. I’m not sure if the previous owner changes the diff fluid. There is a rear pinion seal leak but it’s not a fast leak. Do you think it could be something with the ring and pinion or maybe the diff fluid?
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From: Cool Northern Michigan
That's the thing about the internet. We can't hear a thing. Only you can. You can not describe a noise on the internet. Its impossible.
So, if its not a rear axle fluid issue, it could be one of the six U-Joints. Especially the one near the pinion. Perhaps a needle bearing went south. Perhaps they have seldom been greased.
Sometimes you can grab a driveshaft and just know somethings not right with the U-Joint. Other times there's no clue. Hard to say.
If you change out the fluid, use GM products. If it lasted 40+ yrs, it will last another forty. You will need two Lg bottles of GM lube and one Sm bottle of GM Posi modifier.
So, if its not a rear axle fluid issue, it could be one of the six U-Joints. Especially the one near the pinion. Perhaps a needle bearing went south. Perhaps they have seldom been greased.
Sometimes you can grab a driveshaft and just know somethings not right with the U-Joint. Other times there's no clue. Hard to say.
If you change out the fluid, use GM products. If it lasted 40+ yrs, it will last another forty. You will need two Lg bottles of GM lube and one Sm bottle of GM Posi modifier.
Last edited by HeadsU.P.; Feb 1, 2020 at 04:15 PM.
Team Owner
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From: Crossville TN
Could be U-joints instead of the rear end. But, rear end fluid inspection/change will give you some information. If fluid is replaced and the noise is still there, consider the half-shaft U-joints a a good prospect for that noise.
P.S. Have those U-joints ever been replaced?
P.S. Have those U-joints ever been replaced?
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u joiints usually dont hum, bearings do. I would suspect a wheel bearing, then maybe a rearend bearing. I would take the drive shaft out and the half shafts and spin the wheels and using a mechanics stethoscope listen to the bearings in each wheel, then do the diff.
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So to answer your questions. The u joints have not been changed to my knowledge and will be the next thing I look into. Also the noise does go away after I stop accelerating and is no existent when decelerating. The fluid has not been changed by the pure black color of the fluid which I’m in the process of changing.
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Racer
Joined: Mar 2018
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From: wilmington Ma
So to answer your questions. The u joints have not been changed to my knowledge and will be the next thing I look into. Also the noise does go away after I stop accelerating and is no existent when decelerating. The fluid has not been changed by the pure black color of the fluid which I’m in the process of changing.
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From: wilmington Ma
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If the pinion is leaking I'd definitely start there. Could be the bearing is going and is tearing up the seal. Jack up, put in N and wiggle the driveshaft.
Ideally it would be a good idea if you could put up on jackstands or a hoist, remove the driveshaft, tires and u-joints. Rotate the pinion by hand and feel for roughness. The pinion could still be somewhat tight by wiggling the driveshaft, but sometimes rotating by hand could reveal some bearing 'roughness' which is a tangible sign the bearing is soon to crap out. And when a pinion bearing goes, usually there's little time before lock-up. At that time you can also check the U-joints and even the wheel bearings by doing the wheel bearing test (as in the service manual).
Don't put a floor jack under the pumpkin as they are aluminum and can distort the shape (which who knows ..may have caused your issue to start with).
Ideally it would be a good idea if you could put up on jackstands or a hoist, remove the driveshaft, tires and u-joints. Rotate the pinion by hand and feel for roughness. The pinion could still be somewhat tight by wiggling the driveshaft, but sometimes rotating by hand could reveal some bearing 'roughness' which is a tangible sign the bearing is soon to crap out. And when a pinion bearing goes, usually there's little time before lock-up. At that time you can also check the U-joints and even the wheel bearings by doing the wheel bearing test (as in the service manual).
Don't put a floor jack under the pumpkin as they are aluminum and can distort the shape (which who knows ..may have caused your issue to start with).
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From: Drummonds TN
My 78 had a noise in the rear end as well. More of a chatter around corners after the car had been drove for a good while. A mechanic suggested that I ALWAYS double the posi track fluid amount and ALWAYS use only GM products. No diff drain on a 78 so I pulled the rear end fluid out.. Put in 2 bottles of GM posi track and filled it up. Has not made a sound since and that was at least 3 years ago.