I need help with some definitive and hopefully provable answer regarding the diff service, specifically for FL 204's (m276 & 722.9+). I've been pouring over all the info I can get my hands on but it all pertains to the older iterations.

1st. What fluid do I need? Hypoid gear oil? Fully synthetic gear oil? GL rating? Weight, I.e. 75w85, 75w90, 85w90 etc.? Is it the same fluid for front and rear? The owner's manual for these model years contain zero info. And the info on the web seems to only go up to my12 or is AMG specific.

2nd. What are the capacities? From what I gathered online, again not specific to my car, 1qt rear 1.1qt front?

3rd. The front diff case does not have a fill hole but can be filled in the same manner as the transmission using the exact same adapter? I can verify the similar construction of the diff housing to 2010(?)-2012(?) models with the torx bit drain plug. *see pic* Assuming of course this is in fact the diff housing?


I spoke to 3 people at Motorworld MB (Wilkes-Barre, PA) today. A service manager, he had no clue. A technician, he tried really hard to talk me out of it saying it doesn't need to be done, ever. He mentioned having to pull the axle or driveshaft, cant remember what he said exactly to do the front. I mentioned the transmission service method and he kind of balked at it. He also said those front cases are very sensitive to over-filling and can blow out the seals. Makes sense. I asked about fluid type and he couldn't tell me what they use (I think to try to back up his previous statement of it never needing to have a fluid service done). Finally I spoke to someone in the parts department and told him I needed diff fluid and gave him my VIN without any other info to try and get a non-biased result. After about 10 minutes on the phone, constantly putting me on hold to "check something" lol he said he'd have to look into it and call me back. 4hrs later I call him and ask what he came up with. He said all he came back with was "gear oil" I pressed him for more info, (weight, type, anything specific) and he just said "I dunno" "the pic looks like it says gear oil on the bottle" "it's $60.58".

I hung up.

I know this is a bit long winded and I will get a lot of TLDR's but please try and keep responses specific to this particular set up. Thanks in advance and remember, shiny side goes up.

 

Retracted... Xzero has better info...

 

https://mbworld.org/forums/c-class-w...ce-thread.html

Go over this post for fluid capacities and how to easily fill the front and rear diff in 30 minutes.

 

I must be getting tired. I read over your post and got a lot of the info I've been going off of from it but I guess I missed the 276 in the fluids. Looking at the worksheets you provided (Rear Axle - Oil Change.pdf (130.2 KB) and (Front Axle - Oil Change.pdf (97.8 KB) I think I'm getting confused with all the designation codes. i.e. 204 with code 471 etc. Because that worksheet is calling for 75w140 limited slip? I'm going to try to work backwards with the fluid specification #'s you put up and see what I come up with. Excellent compilation btw. Your efforts are appreciated.

 

From post#2, here are the fluid capacities and specification:

Rear Differential
Type: M272 & M276
Interval: Lifetime (My interval is 100,000KM)
Capacity:
C250 (V6 CDN): 1.0 L (1.06 US qt.)
C300/C350: 1.1 L (1.2 US qt.)
Specification: 235.7

Front Differential for AWD
Type: M272 & M276
Interval: Lifetime (My interval is 100,000KM)
Capacity:
C250 (V6 CDN): 0.6 L (0.63 US qt.)
C300/C350: 1.1 L (1.2 US qt.)
Specification: 235.74

235.74 can be checked out in the Bevo Guide in the same post or you can go off what I used in my thread here:

https://mbworld.org/forums/c-class-w...ce-thread.html

I used Fuchs Sintopoid FE 75W85

Check out post #7 for a super easy way to refill both differentials that doesn’t require removing the axel shaft.