PeachParts Mercedes-Benz Forum - View Single Post - Final drive (differential) seepage on 1987 300TDT (S124)

swogee · #12 02-08-2011, 02:29 PM

I figured I would post an update on the final drive seepage problem on my 300TDT.

Back in Sept 2010, the shop that was doing the work on the final drive examined the axle shafts, as well as all the related parts that were connected to the final drive. The shop replaced under warranty the passenger side axle shaft since it was determined that the run-out was excessive. (Axle shafts are rebuilt units.) The master tech/owner felt that the excessive run-out was the cause of the seepage. In addition the flange seals were again replaced on both sides and the bearings were checked for excessive free play. (The free play was determined to be acceptable.) I thought the seepage problem would be resolved, but in a couple weeks I noticed there was oil splatter on the exhaust pipe and seepage on the bottom of final drive as well as oil on the axle flanges of the final drive. I took the 300TDT back to the shop and they again inspected the final drive, but they didn't think the oil was excessive.

Fast forward to Feb 2011, I am installing the factory trailer hitch and notice there are droplets of oil on the bottom of the final drive and there is oil splatter on the exhaust pipe and oil on the axle flanges. I bring the 300TDT back to shop again and they inspect the final drive and this time they confirm it is indeed seeping again. At this point the recommended course of action is to swap out the final drive for another unit. It still kind of bugs me that the cause of the final drive seepage has not been actually determined. I am an engineer and I like to know what is causing a failure before attempting a repair solution to ensure that the solution will actually correct the problem but at this point there isn't anything else to try.

I have started searching for an ASD differential from a 1990-1993 124.128 but so far I haven't had much luck. I figure if I am going to swap out the final drive I may as well make upgrade to LSD.

As a side note, there are a few other things to note that may or may not be related to the final drive seepage. The rear subframe bushings are cracked so those need to be changed out at some point time. Also the driveshaft bearing support seems to be wearing out at an accelerated rate. The last one that was installed lasted less than two years, and before that it was less than four years. I did start a thread on the bearing support to get ideas on the cause of failure as well.

Any thoughts or ideas are welcome.

Thanks in advance.