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This weekend I changed the rear differential fluid and transmission fluid/filter.
I had the supplies I needed for the front diff service, but didn't find the fill plug... researching this led me to two "facts"
1 - The fill hole is also called the "axle hole" and you have to remove the axle to use it
2 - WTF are you doing? This is a lifetime-sealed-diff. Don't touch it, idiot.
Based on what I saw under there, I'm pretty sure #1 is true. Because I don't like #1, I am also hoping #2 is true.
This weekend I changed the rear differential fluid and transmission fluid/filter.
I had the supplies I needed for the front diff service, but didn't find the fill plug... researching this led me to two "facts"
1 - The fill hole is also called the "axle hole" and you have to remove the axle to use it
2 - WTF are you doing? This is a lifetime-sealed-diff. Don't touch it, idiot.
Based on what I saw under there, I'm pretty sure #1 is true. Because I don't like #1, I am also hoping #2 is true.
Can anyone confirm?
Removing the CV axle just to fill it is a pita. There’s a potential option 3: pump new stuff up through the drain hole.
I’ve had mine serviced. Passenger axle needs to be pulled out. It is “NOT” a life time seal.
front diff holds about .6qt of fluids inside.
I’d highly recommend the service. Replace the seals at the same time to prevent future leak from the front diff. Which is inevitable.
Originally Posted by QuadTurboPrius
I like option 3... but I want option 4 -- do nothing because this diff doesn't need it.
Hopefully someone can confirm that the front diff in this car is lifetime-sealed. Anyone know?
I did a front diff service on my S550 which also has no fill plug. There is an adapter you can thread into the drain hole and pump the correct amount of fluid up into the diff. It may be the same tool that threads onto the transmission pan (and the fluid is added the same way there, but considerably more). No reason to pull the axle and disrupt everything unless you want to do the seal(s).
It was one of the adapters from this kit for my S550 and I'd imagine the thread is the same on the E63:
I think everyone will agree this is a lot easier than pulling an axle. Also, you can pump a small amount extra to compensate for the tiny spillage when you swap the adapter for the drain plug. I barely lost any...
I just ordered the filler plug adapter, thanks for the link Kevm14! is that .6 quart capacity of 75w85 oil a pretty accurate figure for the front diff? On the subject of capacity; is the rear open diff capacity less than 3 quarts of 75w90?
Ok transmission every 40k on M156, M157 and M275 cars (except GL and M for M157 - those retain the 70k interval of non-AMG cars). Rear diff on S model every 40k as well (limited slip).
I don't see an interval for the front diff but I skimmed it quickly just now.
EDIT: I have a theory on the longer interval for the M157 SUVs. Separate transfer case on those.
Ok transmission every 40k on M156, M157 and M275 cars (except GL and M for M157 - those retain the 70k interval of non-AMG cars). Rear diff on S model every 40k as well (limited slip).
I don't see an interval for the front diff but I skimmed it quickly just now.
EDIT: I have a theory on the longer interval for the M157 SUVs. Separate transfer case on those.
Yep - that's what struck me on the front-diff. I found no recommendation in the service schedule for that part at all... very odd. I have the S model.
Hmmm... well, I suppose it's in order then. Thanks all!
Everything under the car looks pristine... no leaks and it looks like brand-new metal on all the gear housings. Because of this, I don't plan on pulling the axle or messing with seals. I will do the drain/fill from the same plug.
So - Does anyone have a direct amazon link to the pressurized fill bottle system with the right bolt thread for this? Derp - I see the link above. thanks!
I did the transmission (6L) with a hand pump and threw it away after... I will not be using that tool again. My hand still hurts.
Last edited by QuadTurboPrius; 05-15-2023 at 06:30 PM.
The reason I would service the front diff at 40k is because there's no way to check the level. For the rear diff I'd at least verify full level at 40k even if you don't change the fluid.
The reason I would service the front diff at 40k is because there's no way to check the level. For the rear diff I'd at least verify full level at 40k even if you don't change the fluid.
Not bad advice - with the pump method shown in the images it would only take a few minutes anyway and it's super easy to get to. I suppose now its just a quest to discover Mercedes' intent
It is possible that they have no interval on open differentials, generally. But, you don't have to try very hard to find plenty of differential failures (front and rear) in the Mercedes world so I figure fluid change (which allows fluid inspection and correct level assessment) is cheap insurance.
It is possible that they have no interval on open differentials, generally. But, you don't have to try very hard to find plenty of differential failures (front and rear) in the Mercedes world so I figure fluid change (which allows fluid inspection and correct level assessment) is cheap insurance.
I’m not saying it should never be changed but I think it’s not necessary every 40k if you have an open diff.
Ok - I've spoken with the 3 Mercedes dealers in my city:
Question "What is the service interval for the front differential, and where is it listed in the service schedule?"
Dealer 1 - Guy who answered phone wasn't sure what I wanted - Language barrier - will have someone call back
Dealer 2 - Quoted me $113 for "diff service" but seemed puzzled that my chassis wasn't listed in their quote tool. They could not identify the service line-item the front diff falls under. They sent me to their expert's voicemail. (clue #1 -- $113 makes sense for rear diff. 10 minutes of their time and $20 of oil. That price makes much less sense for 2 diffs with an axle-out)
Dealer 3 - Initially said 4yr/40k service interval, but stumped themselves looking for the line-item. They went to the parts department and looked up the procedure and confirmed -- this is a lifetime-no-service part on a 2014 E63 S AMG
So - I agree that it should probably be changed now and then... maybe 80k or if the seals are leaking, etc... but all signs point to: Mercedes does not intend for this part to be preventatively maintained.
Last edited by QuadTurboPrius; 05-17-2023 at 11:22 PM.
Waking this thread up, curious what fluid is recommended in the open front diff of my E63 S Wagon? Went into the dealer today, they suggest using the same 75W140 that is used in my rear diff (LSD). Thoughts?
When I was researching this, I think I found that it would be a lighter-weight than the rear (70w85 comes to mind)
And it doesn't surprise me that they may be guessing. It took quite a lot of communication between two dealers for me to discover that this is intended to be a lifetime diff with no service. So... consider leaving it alone
05-13-2023, 11:11 PM
