My '91 300D has about 373K miles. Recently it developed a howling/whining noise from under the rear seat on the drive side. At above 50mph the noise level is almost unbearable with windows closed. I thought the muffler was going and took it to a muffler shop but they said exhaust system in proper order. Now I am thinking it may be related to the differential or axle shaft. Crawled under the car this afternoon and noticed the back side and driver side of the differential are coated with oily dirt. The rubber boots of the axle shafts on both sides look normal and dry though. On the driver the connection between axle shaft and differential is coated with oily dirt as well. I understand axle shaft usually fails when the rubber cone shaped boot cracks and leaks out oil, but can it leaks from the spline when it connects to the differential? Or is the differential actually leaking from the differential pinion?

Assuming the axle shaft or/and the differential need to be replaced, what are the models that I may be used replacements parts from? Does after '90 W124 models share the same axle shafts?


Tan

'91 300D 2.5t 374k miles
'87 300TDT 140k miles

At over 350k miles its probably just a bad wheel bearing.

Good Luck.

David Roseman
Long Beach, Ca

+1 looks to me like a bearing issue

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Thanks for the insights. I will check out the bearings today.


Tan