I'm in the process of replacing the differential pinion seal on my '71 280SE (6 cylinder). The oil I drained out of the differential was very dirty, and it seems to me that flushing is in order.

I found lots of very helpful information on this site about setting the grooved nut properly, cleaning the differential valve, etc. but couldn't find anything about a differential flush. What fluid should I use? I was thinking of using ATF and running the rear wheels under no load for about 10 minutes before draining.

Thanks for any insights.

Bill in Maryland

I would just fill it with the required oil and drive about 50 miles then change it again. Remember to drain it with the car level and wheels down or it won't all come out.

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Brad



1966 230 SL
2005 CLK 500 Cabrio
2013 C 300 4 Matic sport 3.5

If you have any positive camber there will be oil trapped in the axle tubes that won't come out. You may need to jack one side up and then the other so the oil will run out. Insure the axle is warm from driving.

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Tony H
W111 280SE 3.5 Coupe
Manual transmission

Past cars:
Porsche 914 2.0
'64 Jaguar XKE Roadster
'57 Oval Window VW
'71 Toyota Hilux Pickup Truck-Dad bought new
'73 Toyota Celica GT

Thanks to you both. Since my initial post someone who is extremely knowledgeable about these cars gave me some advice that I'll post here in case it may be of help to others.

He recommended using 1-2 cups of kerosene and running the wheels at no load for 2-3 minutes before draining. He also said to consider using a magnetic drain plug to catch any metal filings.

I see no need to do anything more than Brad suggested in his post above. Anything else seems to be not only overkill, but might also cause more problems than it solves.

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Len
'59 220S Cabriolet-SOLD and living happily in Malta
'83 240D 351,500 miles original owner-SOLD
'88 560SL 41,000 miles - totaled and parted out
https://sites.google.com/site/mercedesstuff/home
'99 E300 turbo 227,500 miles
'03 SLK320 40,000 miles - gave to my daughter
'14 Smart electric coupe 28,500 miles
'14 Smart electric cabriolet 28,500 miles
'15 Smart electric coupe 28,000 miles

Might not be a bad idea to check the integrity of the rubber axle boot and its band clamps while you're down there. Last summer one of the clamps rusted thru on me and I lost quite a bit of the oil on the garage floor.

Tom

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1972 280SE 4.5