Hi everyone, I have searched through numerous posts, but I'm stumped. My maintenance manual with my vehicle doesn't list any service interval for front and rear diff fluid change. There also isnt any repair procedure I can find in WIS for changing the fluid. This leads me to believe there is no fluid change required in the 20144 X204. I see many forum members changing it anyways.

Does anyone else know if the 2014 has any service interval for the fluid, e.g. did I somehow misread the maintenance booklet?

 

It’s a mb , they like to sell those uneducated on basic car requirements that they need less maintenance than other vehicles. trans fluid with no dipstick to check level, with to long an interval , 9000 mile engine oil changes , differential fluid for life 🤣🤣. I had mine changed at about 80000 , now I know what its condition was . 80/100000 was always a standard length I thought . I think You need a pump to fill one of them . Change it !

 

There are no recommended service intervals for front and rear diff. I serviced mine wanting to inspect the condition of the fluid for the age and mileage on the car.

Draining/filling the rear diff procedures can be found in the Maintenance section of the MB manual.






Draining/filling the front is found mentioned in the Transmission and Drivetrain section under replacing the right side diff seal, maybe somewhere else but cant think of it. Since unlike the rear there is no fill plug on the front they say to fill thru the right side axle hole. I did not do that and instead pumped in the new fluid thru the drain using the transmission fill adapter. The front diff drain plug even uses the same gasket as the transmission drain plug.

 

Maybe the answer would be obvious if I were lying on my back under the car, but, after you fill it, how to you put the drain plug back without getting an oil shower when you take the fill adapter out? The trans has that standpipe in it, but I can't imagine the differential would have one, too.

 

Unscrew the fill adapter and quickly screw in the drain plug.

In my photo above I have a quick connect that I unhooked after pumping the oil in. This kept the oil from draining back out. Then unscrew the adapter slowly and once its out plug the hole with my finger. Then get the drain plug ready and put it in. Just had a few drips of oil when done.

I measured the old oil that came out, caught it in a large measuring cup. It was around 0.7l so I pumped in 0.75l to account for drips. I was fully prepared to do it over if I somehow screwed up and too much oil came out. When I did my transmission I dropped the drain plug in the container of fluid and had to fish it out when I was setting the level.

 

Thanks for this Tim.
How was the condition of your fluid and what is the mileage on your car? Do you think it needed to be changed?

 

I bought the car with over 100,000 miles and while the Carfax shows it has been serviced every 10,000 miles at a Mercedes dealer it doesnt specifically mention anything about the differential.

I replaced the diff fluid at around 130,000 miles. The fluid in the rear diff looked great almost new condition which surprised me and I remember thinking I did not even need to change it. The front diff fluid looked ok, like typical used gear oil and i remember just being glad I replaced just to be able to inspect the condition.

If I had to guess I would say the rear may have been replaced at some point before I bought the car just on how good it looked.

Glad I did it just for piece of mind. Seems the proper amount came out indicating no leaks, the fluid looked good no pieces of metal that would indicate abnormal wear.

 

thanks, great info. Which fluids did you use for front diff and rear? I see lots of kits and variations.

I already have the fill adapter to be able to fill into the drain hole in front diff. Just need to order the rear drain plug and a new washer/seal for the front diff screw.

 

I used Febi 75W-85 GL5 gear oil. It meets the MB spec and they sell it at IDparts which is close so I can pick up my orders and dont have to pay shipping. For the front and the rear two bottles was plenty and have a little left over. It was only $18/bottle at the time and seems prices have gone up. They also have the Fuchs that meets MB spec.

I did buy a new rear drain plug just in case I had trouble with one of them but I ended up reusing the old ones since they were fine. I reused the front drain plug and just replaced the gasket. The front diff uses the same drain plug 000908012009 and drain plug gasket 007603012102 as the transmission pan. I bought a few of the gaskets at FCP when I was placing an order. They are just 12mmx16mmx1.5mm and can find them at your local auto parts store cheap if you need one.

 

Thanks, I got 2Q redline 75w-85 GL5, and the pump to pump into the drain hole

 

Do you have the adapter for the pump to drain hole?

 

Notes from when I changed mine, it was at almost 300k km, oil looked better than expected. Its was Fuchs juts to be clear

 

Thread dope is better than Teflon tape. Teflon tape turns into tiny threads of Teflon and can get into things it shouldn't. Maybe not a major thing in an axle, but can be bad in other places, like lubrication and fuel systems. Teflon tape is fine for household plumbing.

 

Haven’t done plumbing work in years but I switched from the white to pink Teflon tape, found it better, I put that over the rear plugs. Not an expert on Teflon, so not sure if a certain colour would be better around gear oil?? I think the pink and yellow stuff if just thicker and more resistant to shredding.

 

I will use Loctite 243 on threads. Bought the bottle years ago and since I hardly every use it its lasting me a long time. I chose the 243 because I read it is good for parts that may not be cleaned spotless which is most of the things I work on. I like to use PB Blaster and Liquid Wrench on rusted bolts.

The front diff drain plug I got off easy but the rears were really tight and made harder by not having much leverage. I ended up using my Dewalt 1/2" DCF901 impact wrench to break them loose.

 

old fluid, new fluid, front diff, 102k miles