I have a rear differential bearing that is roaring. It has been doing this since I got the car, it is no worse than it was years ago, I have put off fixing it due to the car not being driven, now that I am driving it some I need to take care of this. Symptoms:

• Constant roar, it gets a little louder at higher speeds
• turning does not seem to effect the noise
• makes no difference if it is under load or not.

Can someone help me determine which bearing is the culprit?

THX~!

 

Sorry - left this out....

1970 Olds 12 Bolt rearend, if that matters...

 

Best bet is to open the cover and take a look. Are you sure it's not an axle bearing?

 

Not really sure, someone told me that an axle bearing would change sounds cornering. It does not appear to do that.

I have new axle bearings and new carrier bearings, I think all of these can be changed without having to mess with the settings (pinion depth, etc.) - Is that true?

 

IF you have one bearing going then all the rest are not far behind NOT to mention the debris from the one that is the problem is eating the others up too. Jim

12 bolt olds rebuild kit is 95.00 includes the following parts

2 carrier bearings and races
1 inner pinion bearing and race
1 outer pinion bearing and race
1 Pinion seal
1 pinion crush sleeve
1 pinion nut
1 rear inspection cover gasket
1 carrier pack of carrier shims
1 pinion pack of shims
1 marking compound and applicator brush
10 ring gear bolts
1 booklet to help you with your set-up pattern and torque specs.

You will have to check the axle bearings as they need to come out if you are doing any differential carrier or pinion bearing anyway. Jim

 

When the carrier bearing was out in mine, it would only roar when coasting. Under load it would take the slack out of it and run quiet... My thinking is that it is something else. A buddy who had a bad axle bearing had a constant roar also, not sure if it changed when he cornered or not... Remember those bearings are potentially 40 years old and probably should be replaced anyways...

 

Yep I agree Just do them all. IF you have access to someone that can check the axle straightness do that also. Jim

 

I understand what you are saying....
However I want to avoid the "set up" part of it. I'm not sure I would trust myself to do this and I certainly cannot afford to pay hundreds of dollars to have this done. I have had carriers out of rear axles before and put the shims back where the were with no adverse effects.

I am torn now, I already have all of the axle and carrier bearings, races and seals and the car only has 136K miles on it. But before I want to get too deep in resetting the rear gears up, I may look for some other rear axle to hang under it as it is.

 

While a complete rebuild of the rear axle will probably cure the problem (assuming that all variables are set correctly), it might be less cumbersome and less expensive to fix only the offending problem. The first step is to perform an accurate diagnosis. Either put the vehicle on a lift or jack the rear so the wheels are free to turn. Be sure to secure the support so the vehicle will not fall on you. Operate the entire driveline with the engine. Use a noise amplifier or stethoscope on the housing nearest each bearing. When you get to the failed bearing the noise should be loudest. Keep in mind that gears, tires, and brakes have also been known to make noise ("roaring"). After the source of the noise has been identified, make an appropriate repair, and the problem should be resolved.

 

Agreed, the sound reminds me of truck tires on the pavement. I know it is not the tires, since no matter what wheel tire combo I am running the noise stays the same. I will attempt what you suggested, but it will be a few weeks since I am so stinkin' busy!!! ARRRRG!