so i thought that the "whine" from my rear end was perhaps a bit much, no bother really, so after changing the gear oil, i jacked it up and ran it through the gears, wheels off the ground, and it sounds like a washing machine -- no metal in the oil -- i hope someone will say that "they all sound like that" -- and other than the usual rear end whine, it does not make any noise when driven -- this car is new to me, only driven about 6k, and hads 120k on it

and it is definitely from the differential, as i isolated it with my stethoscope, heard best from up front, where the pinion exits the diff case

i hoping this noise is due to running it off the ground, which i usually don't have occassion to do on my cars

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81 240D: Lola
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They usually make no noise at all up or down. Sounds like you have some damaged gears, either ring and pinion, or spider gears. Pull the cover and look at them all. Any lines, pits, chips, or other obvious wear on the faces of the gear teeth are your source of noise.

If the noise is much louder or different when the tires are off the ground, that would point more towards the spider gears being damaged, which you may be able to replace, certainly easier than the ring and pinion gears. Or you could weld them for some off roading.

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The pinion bearing is another potential source of noise. I suggest that it is more likely the problem.

Check the rear diff mounts? Could it be drumming in the frame rather than the internals?

cheers!

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cheers!!

Don't worry about it. My differential has 350,000 on it.

My car is a symphony of sound when it starts up on a really cold morning. Between my non electric back up squeal and and groan I sometimes get when I turn the wheel (fluid/belts/hoses are fine). I just let it go and drive and drive carefully when the engine is cold. Once she's warmed up the car just goes.

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The groan could be a dry lower ball joint. I had this happen for a while and got so tired of it, I finally got rid of the problem. A squirt of axle grease under the boot got rid of it. Joint was otherwise tight.

It would be unwise for him to not worry about loud noises from the diff. If its howling associated with gearing surface imperfections, well he could probably go for hundreds of thousands of miles on that, BUT, if its something like the pinion bearing like Matt L. suggests, that seizing up could be a major problem and result in major damage.

He should at least go so far as to know what it might be. Easy enough to replace the bearing, or even the whole diff than to repair a lot more damage or have something fail in a dangerous driving situation.

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Yeah, I had my indy replace the lower ball joints and the ball joint rubber thing pulled upward from the joint. It's intact all the way around, but I can move it upward.

I discovered this after I did my oil cooler line job and the effort involved to fix it was just too much for me. I injected some Kabota tractor grease into the fitting and that did the trick. I'll just do this every oil change and call it quits. I've been exhausted from all of this work on my car.

Definitely agree to take a look at it. Removing the differential cover isn't that hard.

My differential after a certain speed makes a whirr noise that gradually increases with speed. When I had the cover off I didn't see anything out of place.

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