I would like some ideas of what this noise could have been. This is on my 84 500SEL with 299K miles.
We were going to the NC coast, about 200 miles. At about 150 miles we had been running 70 mph for about 100 miles. Everything great (love this old car). We came up on a 60 mph zone known for their speed traps so we slowed down to 60. Started hearing this very faint ticking/taping type noise which seemed to be coming from the rear. Hard to explain. I tried speeding up, slowing down +/- 5 mph. No change. I shifted to 3rd gear to increase engine rpm and no change. Tried swerving left to right and right to left and no change. It seemed to me to be about the speed of the wheels turning and thought maybe we had picked up a rock or piece of metal. We could not feel it, only hear it.
I pulled off the road at an exit and stopped at a gas station. As we pulled off the highway the noise went away. I felt around the tires and didn't find anything. Looked under the car and didn't see anything that looked strange. So we continued on our way.
A short distance down the road we were up to 60 again and could faintly hear the noise again and it slowly faded away.
The next day we made the return trip and never heard the noise again. Got home, pulled all 4 wheels and everything looked fine. No evidence that the brakes may have been hanging up. Could not fine any play in the bearings or axle shafts. No cuts or bulges on the tires.
Has anyone experienced anything like this? Do you have any ideas what it could be? Wife and I are both sure it was from the rear and outside the car.
We are planning to leave Monday morning going to the Outer Banks, NC. Thats about 350 miles. I'm not worried, but a little concerned not knowing what the noise was.

Thanks for any thoughts.

PaulM

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84 500 SEL (307,xxx miles)

Check the differential fluid and your rear flex plate.

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1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Thanks TnBob, the differential oil level checked about 1/4 inch down but the car was jacked from the right rear making the car lean to the left and down in the front which I think would account for the 1/4 inch. The rear flex disk looks good, no cracks and bolts are tight.
I am running Lucas 85-140 gear oil, just changed about 7000 miles ago. I change it every 30k and have been doing it for the last 12 years.

Thanks for the reply. Anything else you can think of?

PaulM

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84 500 SEL (307,xxx miles)

The only other obvious to me would be an axle ujoint that is trying to run dry.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."