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Diff whine.. heavier gear oil?

mattd1205

Member
Joined
Dec 5, 2014
Location
Harbor City, CA
Ive got a ‘91 245 with 172k that developed a differential whine recently. I had a carrier bearing issue about a month ago and the bearing was replaced. The car was dead silent for about two weeks and then it started whining from 65-72mph when the throttle is engaged. When coasting at those speeds the whine is not present. I took it to a mechanic and he put my car on the lift and accelerated to 70mph and the noise wasn’t audible then either. He test drove it and heard the offending noise and said the differential was the culprit. He changed the gear oil in it and refilled it with 80w90. The old 80w90 was in there for 2 years and about 20,000 miles. It’s better now but still pretty annoying. I have a feeling a rear axle from the junkyard is going to be necessary soon. Can I fill it with some heavier 80w140 to buy me some more time?

Thanks
Matt
 
You may have a bad wheel bearing (not carrier bearing).

The thicker oil should be fine I expect.

I?ll have to check the front ones a little better. We didn?t hear anything from the rear axle bearings when it was on the lift. Would the carrier bearing or wheel bearings cause a whine at these specific speeds and nowhere else?

Thanks
Matt
 
The Lucas gear oil says it's made to reduce whine. It worked for me. But I would also check the wheel bearings and driveshaft bearing/support. They can also make a whine when they are worn.
 
It's probably the pinion bearings. They aren't that hard to change, especially if you have the factory tools like I do.

Hit me up if you want me to look at it. You're not far from my shop.
 
Would the carrier bearing or wheel bearings cause a whine at these specific speeds and nowhere else? Matt

Last time my carrier bearing went bad it was 'singing' when on the highway. Wouldn't do it in town. The singing seems pretty typical of that failure. Would make a high pitched 'eeeeeeeeeeeeeee' noise. Never happened in town. Only around 60 or so. Bearing was completely roached. I couldn't believe that it didn't seize.

It ate an axle bearing race about a year after that. That was more of a grinding noise. Would change pitch if the wheel was loaded on its side (sweeping turns). Wasn't apparent until I pulled the passenger outer race and wiped off the grease. I had previously put the car up on jack stands and ran through the gears. Since the weight wasn't on the tires, it didn't grumble - only when the weight was on the wheels.
 
Either backlash, carrier bearing preload, or even the bearing you installed.

When troubleshooting, always return to the scene of the most recent crime.
 
I had a wine and clunking and a howling sound when on the open road witch I thought was the diff but after replacing a buggered automatic trans it all stopped.
 
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