I have a 1979 300 SD. I just purchased this car two months ago. It has developed a humm in the rear end. It is a hit and miss situation, it happen on occassion. The noise happens when you are accelerating between 50 and 60 mph. We had a Mercedes mechanic look at the rear end because of a clunking noise. He said it was fine for the amount of miles, 224,000. Do you have any idea what it could be?

Thanks for you suggestions,
Jim & Colleen

I agree with Jeff. Here is a tip to help confirm this and eliminate the wheel bearings, which should hum all the time if one is bad. The next time you are cruising along and hear the noise, veer the car to the left and then right, a sweeper type of corner is perfrect. As you turn, it loads the outside wheel and unloads the inside wheel. The bad wheel bearing should stop humming when unloaded. If it is the differential, the noise will be constant.

Please use caution when doing this. DO it on a quiet back road and have a passenger keep an eye out for other traffic.

I don't know what happened, but somehow my follow on post overwrote Jeff's advice that it was the ring & pinion. I think this was well written and good advice, but can not recite it from memory. Jeff, are you still out there?

Thanks whunter for keeping these posts in front of us newbies.......

__________________
Eric Boyles
1980 450SL