What parts are required for the rear differential flush?
Thread Starter
Member
Joined: Aug 2025
Posts: 104
Likes: 20
From: Texas
2015 ML350, 2020 BMW X7, 2005 LS430
What parts are required for the rear differential flush?
So I went to the dealer today and they said labor for the differential flush is only $60, and it's time to replace the fluid anyways, but they were charging an absurd $180 on the parts. They said I could purchase parts on my own but it would have to be mercedes original. The thing is that the fluid costs $80 for 1.05 quarts and the differential needs a little bit more to my understanding, not exactly sure the exact amount, maybe someone can chip in. If its like 0.10 quarts short would the dealer hypothetically fill the rest or make me purchase a second bottle? Also what bolts/washers need to be replaced? That too I had a reputable indy shop here in the Dallas area that's well known quote me for a differential service and in their quote they specified 75w90NS Gear Oil which isn't the same that Mercedes would sell for the vehicle. Mercedes recommends 75W-85. Is 75w90NS Gear Oil the wrong kind or is it a higher performance version that would help the vehicle a little bit? I don't know much about these fluids.
Out Of Control!!
Joined: Apr 2019
Posts: 12,058
Likes: 6,848
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
use best supplies
75W-85 has a split hair better gas mileage
75W-90 has a tiny bit of viscosity reserve
75W-90 PAO is really what's best for Texas temp swings... won't cost $80 like a quart of MB stock oil. The joy of doing this rest in using better supplies.
Diff plugs are tapered cone shaped without washers.
75W-90 has a tiny bit of viscosity reserve
75W-90 PAO is really what's best for Texas temp swings... won't cost $80 like a quart of MB stock oil. The joy of doing this rest in using better supplies.
Diff plugs are tapered cone shaped without washers.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,191
Likes: 1,782
From: Colorado
G550
My G550's rear diif has a metal drain plug and a rubber fill plug. Dealers usually replace both because they don't want to bother cleaning them up and losing margin on new replacement parts. The metal plug threads are easily cleaned with a small wire brush. I used some Permatex teflon thread sealer also. The threads are tapered, but a bit of sealer lubes the metal to metal contact.
Out Of Control!!
Joined: Sep 2018
Posts: 14,707
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From: unbegrenzt
2017 GLE350 4MATIC
Read the DIY in my signature.
Parts:
oil
fill plug
drain plug
https://mbworld.org/forums/gle-class...report-15.html
Parts:
oil
fill plug
drain plug
https://mbworld.org/forums/gle-class...report-15.html
Last edited by chassis; Mar 14, 2026 at 10:54 AM.
