I just took my 2007 Roadster in for B service at 32K miles and the dealer says that they recommend rear differential fluid replacement (1.4 quarts of MB stuff), costing $250.

Hmmm. The Owners Manual doesn't mention this not-inexpensive maintenance recommendation anywhere, A, B or Additional Maintenance procedures. I asked the dealer to point me to where it is recommended and he had nothing.

Elsewhere in this forum, someone mentioned that since it wasn't in the Owner's Manual, it is really permanent and never needs to be addressed, but then also said that in an MB forum, they recommend replacing the fluid every 30-50K miles.

Anyone have a service manual with better input or suggestions based on your experience? I would think this should be pretty straight-forward, you either do or do not and with no mention at all in the Owner's Manual, I'm thinking not?

Thanks!

 

First off... $250 for a diff fluid change is crazy! The most I've seen is $90. It's really not that hard I just did mine at 42k and it only took about 30min (cause my tools are never where I leave them) and a bottle of fluid is about $20. I believe the manual says too change it at 80-100k.

 

i did mine at 40k and used mobil 1 75/90 full synthetic gear oil. 2 bottles i think was 30$ and the small hand pump was 6$
remove the fill plug first then the drain plug. refill and your done! took all of 20 min.

 

I took my 2004 into a dealer for an oil change, and to have it checked out before leaving on a cross country trip, last month. When I got home from the dealer, I noticed that the paperwork said my differential fluid was dirty. I called them to find out about this because my manuals make no mention of a time line for replacing this and the car only has 29000 on it. No one was there that new anything about it. But since it had been mentioned on my receipt if anything went wrong with my differential it would be my fault and not covered by warranty. Even though they had not pointed it out to me. And they could not get me in for several days. I looked up what kind of fluid it needed and took it to Goodyear and had them do it for $85.00. I do not think Chrysler wants to work on Mercedes now that they are Fiat. $250.00 to change 1.4qt of diff fluid after a $155.00 oil change! The last oil change they gave me was, out the door at under $95.00. Sounds paranoid I know, but I think they want out of the warranties and are looking for an excuse. I always thought one day I would put a Hemi in it. Now I think Lantana has the right idea.

 

The dealership I go to has a board up with specific maintenance schedules for cars at different mileages. At the bottom, in small letters, it says that it's a combination of dealer and manufacturers suggested maintenance. Of course the dealer would like to see your car more often, thats why some customers are treated like royalty when they come in, it's because their credit card is helping put the owners son or daughter through Yale.

 

I don't know about the rear end, but it is known that dealers have their own recommended maintenance outside of the what the factory wants. Theirs is based on dollars and can include such things as a Transmission flush, engine flush, differential oil replacement, radiator flush, and on and on. My bottom line is it is a factory recommend service I'll do it; if it's a dealer recommended service I won't. Outside of money down the tubes it has been know that the dealer charges for the service, but the service is not performed (can't say whether it is a lazy mechanic or a corrupt dealer), but most people wouldn't even know if the service was performed,

I'm still looking to see if the factory recommends a rear end fluid change...

 

Service manual say refer to owner's manual and I could not find any reference to changing it. I even looked in the maintenance schedule book.

 

I intend to replace my rear differential fluid and gearbox fluid once the weather improves for the following reasons:

1, The oil is not cooled or filtered in anyway.
2, Due to the above, the oil will contain fine metallic particulate which will if left untreated accelerate wear.
3, Manufacturers are only interested in the car being reliable for the warranty period. After that, they couldn't careless as the type of people that buy a brand new car, are likely to do so every 3 years. (Here in the UK anyway).

For 30 minutes of your life and the cost of a bottle of oil, its gotta be a worthy investment.

 

See some of the rear diff comments in the attached link. It's a simple, inexpensive procedure.

https://www.crossfireforum.org/forum...-required.html

 

Here's the information I can find on the rear axle (differential).
I checked the Owner's Manual, Service Manual, and TSBs through 2006.

Service Manual:

Quote:
DESCRIPTION - DIFFERENTIAL LUBRICANT
Note: Refer to the Owner’s Manual for the recommended differential lubricant change intervals for this axle.

Rear Axle Fluid Only use synthetic SAE 75W-85 axle lubricant that meets MB 231.1.
Reduced axle durability may result if an unapproved product is used.

1. Drive the vehicle until the differential lubricant is at the normal operating temperature.
2. Raise and support the vehicle.
3. Remove the differential housing fill plug (1).
4. Position a drain pan under the differential housing drain.
5. Remove the differential housing drain plug (2).
6. Drain the differential housing completely.
7. Install the differential housing drain plug (2). Tighten the drain plug to 50 N·m (37 ft. lbs.).
8. Fill the rear axle to proper specifications.
9. Install the differential housing fill plug (1). Tighten the fill plug to 50 N·m (37 ft. lbs.).

 

Dealers assume you are stupid about fluid changes. Airpark Chrysler Scottsdale, AZ recently repaired top end end oil leaks on my '06 coupe under warranty at 15,000 miles. Recommended the differential be serviced. Rip off attempt.

 

heres a tip
make sure the fill plug is loose BEFORE removing the drain plug. these plugs can be very hard to get out due to lack of service. if you drain it first and cant get the fill plug out your a screwed pooch!

 

Excellent point.
You'll notice it is step #3 or the first thing you do after you get under the car

 

Everything is a matter of perspective.... Being a screwed pooch is not always a bad thing is it? LOL

 

Anyone use the REDLINE 75W85 gear oil in the rear differential? It is the only 75W85 I can find.
The REDLINE container does specify MB235/x but not MB231.1
The website for the product however DOES include MB231.1, who to believe?
Last thing I want is to screw up the differential.
Alternately, do you know of a source for the 231.1 oil?

 

Mercedes or Chrysler carry it as far as I know it has not been discontinued. You only need 2 bottles, one for flushing and the other for filling.

 

I looked on FCP Euro and put in 2003 Mercedes SLK 320 differential gear oil. This is what came up:
https://www.fcpeuro.com/Mercedes~Ben...l%20gear%20oil

 

Thanks Gents, I'll try the MB dealer first.

 

Diff oil Febi 48785
Trans fluid Febi 36449

 

Amazon has 75w85 Redline Synthetic gear oil available: