The dealer told me the same thing. They said they looked up the VIN on MB master computer list.
I said "Look....the owners manual has a insert that says SPECIFICALLY this needs to be done."
Do you want me to snap a pic of that document/
Anyway, I track my car and had just returned from beating it up on the track for two hours so I insisted and they changed it.
About $225 including putting nitrogen in the tires also a big help with an overheating right front.

 

Anyone with experience have any opinions based on the pictures? I don't know if what I'm looking at is normal or not, or would support the idea that a diff fluid change is necessary.

 

Yes and yes. Limited-slip diffs have clutch packs with friction material that breaks-in, sloughing off surface fibers. It's why all LSDs have initial fluid changes. This has always been true and I no idea why some MB regions are saying it's not needed.

 

Does the new electronic differential that the 2019 C63s features make any difference whatsoever? IIRC, that system was adopted over for the C63s from the AMG GT. Does the GT require a change of fluids at 2500 miles?

 

I've never thought of checking that, but there is no note in the GT owner's manual about having to change the fluid after break-in as far as I can see. I searched the online manual. It's important to understand that the 2019s don't have LSDs. They have electronic locking differentials. Yes, they still use clutches but differently and electronically controlled. The C63 (non-S) used to have a mechanical LSD, but now with the 2019, both variants have an electronic locking differential. It has been said before, that the fluid change was really only meant for the mechanical LSD. Notice that the note in the user manual says locking differential, not electronic locking differential. Another data point is that my Audi RS5 also has an active rear differential with two multi-plate clutches. While the service manual calls for regular fluid changes every 30k miles if I remember correctly, it didn't call for a change after break-in. I actually spoke to AMG Germany while I was there. I did European Delivery and was trying to figure out if I need to change the fluid while I'm over there. AMG Germany told me it's no longer necessary. So take it from the horse's mouth. I did end up changing it due to all the confusing that is going around this topic and it can't hurt changing it, but at this point I'm convinced that it is indeed no longer necessary and it's just a matter of not all regions have the latest updated information yet and AMG never bothered to clarify that the initial required fluid changes was really only necessary for the mechanical LSD in the pre-facelift C63 non-S. Also, the MCT transmission uses clutches and there is a startup wet clutch instead of a torque converter and there is no requirement to change the transmission fluid after break-in. If it was about clutch material in these electronic clutches, one would expect to have to change the transmission fluid as well.

 

BTW, just one more bit of information. I just checked the German Online Owner's manual and compared it to older versions (My mother tongue is German, so no lost in Google translation stuff). The language in the latest version has changed. It now says the fluid change is necessary depending on how the car is equipped. Not sure what equipment would warrant the fluid change, but then it further states to follow the break-in instruction sticker on the windshield in regards to whether it is necessary. As many of us including myself have found, our cars break-in instruction sticker says nothing about a required differential fluid change. Previous models and it seems some early 2019s had the sticker saying the fluid needs to be changed. I'm wondering now if there was a change to the differential mid production. When I talked to AMG Germany, they specifically checked for my VIN, and told me my car doesn't need it, which would be inline with not having a sticker saying it needed it.

 

The VIN check could also be just to confirm if your car has an electronic LSD or not, if there is correlation between the two like you mentioned earlier. Yes, still doesn't explain why it was still on the sticker with earlier 2019s and the pre-FL models.

 

The electronics merely make the actuation of the LSD smarter; it's still a clutch-mediated LSD at heart. It's possible that the clutch material was changed at some point to something that doesn't initially slough fiber but that would not have anything to do with electronic vs. non-electronic. My E63S had the sticker on the windshield and they were all delivered with electronic differentials.

The crud in that picture from a rear-end that supposedly didn't need a break-in fluid change should end the discussion.

 

Again, for the record, those pictures were of the differential fluid removed from my car: a 2019 C63s at 2500 miles. My vehicle did have a break-in protocol windshield sticker, but that sticker did not make any mention of a post-break-in differential fluid change.

My tech was adamant that he checked every source available to him to find guidance about whether the diff fluid change was necessary. He could not find a single service interval sheet or directive to indicate that it was required or even recommended. That said, when he showed me the fluid that was removed, he was of the opinion that it wasn't terrible but maybe not quite as clean as he may have expected it to be based on the new do-not-replace protocol.

 

What about the manual, page 13?
https://www.mbusa.com/content/dam/mb...n_Operator.pdf

 

The manuals are not without mistakes, and unless yours is in German, it's a translation where things can get missed. As I posted above, the latest German manual says to follow the sticker in the windshield, FWIW. This is not uncommon BTW. Stickers and labels in the actual car are often used to correct or override information in the manual.

 

I have a factory sticker located top left drivers side windshield. It says rear differential fluid change 1800 miles!

 

what country are you in? I just picked up a 2020 USA model this week and it has the 1000 mile break-in sticker on upper left windshield but no diff oil change sticker. But the manual DOES mention it. Freaking weird that this isnt more consistent.

 

US. Germany built coupe

 

. Wow. Same car as me but I had no sticker. Was yours a separate sticker from the break in period sticker? I even looked at the breakin sticker to see if it mentioned the diff but it doesnt.

 

Mine a 2019. No- one sticker. I’m having it done just in case I keep beyond the warranty period. Doubt that I will. Never do. Good luck

 

I would use the MBUSA.com service plans as the reference. When you log on to schedule service, there are all these options you can choose. One of them is the 2000mi differential service. Just use that as a guide...

 

2019 coupe - had it done for free in UK. I have read conflicting views about its necessity - even from Mercedes themselves - but if it's free it can't do any harm.

 

Seemed like this is the latest one i could find on the diff fluid for the facelift .. I have my car in for service to replace the rear carbon diffuser that had the small peeling around the sensors and a recall for the drivers assistance software as well as an oil change as i like to do them around 4-5k miles... anyways they told me that the car needs the diff fluid changed and they are doing it under warranty.. i have a 2019 with a mid early-feb/19' build date. I have around 5k miles on the car now. I thought it was odd since soo many said it wasn't needed on the facelift.

 

My dealer said that it’s not needed on 2020. I am getting it changed anyways along with engine oil.

 

I brought my 2019 C63S to the dealership to take care of Idle coilpack issues (CEL) and parking sensor issues, and also did the rear diff service. It was less than $200 so I just went forward with it. I was also expecting some confusion wrt this service because of the mixed advice, but the dealership didn't offer any resistance for this.

 

Any chance your dealer doesn't want to be bothered or just doesn't know? Mine was assembled in Oct/Nov 2020. I'm at 660 miles currently. The AMG supplement clearly shows it being required at 2,000 miles in the maintenance matrix. When the time comes, it will get changed. I'd rather be preventative....

 

They checked using my vin in their system. He didn’t dismiss it, he dug in few times to confirm.

 

Mine is a February 2019 build. I just had it done last week. Free of charge.

 

Just got mine done. Cheaper than I expected.