Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help

Go Back   PeachParts Mercedes-Benz Forum > Mercedes-Benz Tech Information and Support > Tech Help

LinkBack Thread Tools Display Modes
Old 06-17-2013, 12:59 PM
Registered User
Join Date: Dec 2002
Location: ohio
Posts: 297
Whiney Noise from Rear of 1991 M/B 300SE

Just as my car reached 100k I decided to change the fluid in the differential. I was told that Walmart synthetic 75W-90 would be fine. So I changed it and all seemed well. A few months later the car was on the highway and after about 1 hours worth of highway speeds I got a noise coming from the rear and I thought a rear wheel bearing was going out but the car made no noise around town. All seemed well until I got on the highway and after about an hour at highway speed the whining noise came back, so I decided I needed a rear wheel bearing. None of the 3 M/B garages would be able to do it I was told by them.

In searching this Forum I saw several posts that said the whining noise could be caused by the type of differential oil used. So I thought I would give it a try and put in M/B hypoid oil 85W90. I just got back from a Fathers Day trip on the highway at high driving speeds and much to my surprise the noise had vanished on the to and fro trips. Thank you AGAIN to all members of this forum as you saved me by allowing me to keep this wonderful automobile.

Reply With Quote
Old 06-18-2013, 02:48 PM
bhatt's Avatar
Registered User
Join Date: Apr 2000
Location: Oakville, Ontario, Canada
Posts: 421
I can't answer your question exactly, but I had kind of the opposite problem. So can confirm that the diff oil DOES make a huge difference.

Had a W126 with the same noise you describe. Tech looked at it and said both rear wheel bearings looked good, but the left side looked a "very little bit" more worn than the right. He didn't want to change them, saying it was rare for a W126 rear wheel bearing to die.

I made him change the left one. Noise still there.

Replaced the diff oil myself and the problem went away completely. I drove the car another 100,000km (60k miles) before I sold it and the noise had never come back.

So for sure it's the diff oil.

I would avoid the WM stuff. I put Mobil 1 in it (not sure what grade but I believe there was only one grade that MB approved)

Look up the MB list of approved oils, buy the Mobil 1 version, and change it.

Not too expensive as there isn't much oil in there at all.
'83 300SD 335,000km (207k) mi SOLD
'87 560SL 163,000km (101k mi) SOLD
'86 300SDL 356,000km (220k mi) SOLD
'92 500SEL 250,000km (155k mi) SOLD
'90 300SL 140,000km (87k mi) SOLD
'01 S430 260,000km (161k mi) SOLD
'03 SL500 167,000km (104k mi)
'07 GL320 CDI 4MATIC 289,000km (162k mi)
'07 S550 4MATIC 170,000km (105k mi)
Reply With Quote
Old 06-18-2013, 07:35 PM
Registered User
Join Date: Dec 2002
Location: ohio
Posts: 297
I almost changed my rear bearings too. I was also told they hardly ever, ever go out on an S-class. Thanks.

Reply With Quote


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -4. The time now is 02:38 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Peach Parts or Pelican Parts Website -    DMCA Registered Agent Contact Page