Do you really have to change the fluid every time you change the engine oil?

 

I very seriously doubt it. I'll have to check the manual, but usually diff fluid will have a change interval of between 30-60,000mi depending on manufacturer, fluid type, limited slip type, and driving style.

 

I just checked the owners manual and it doesn't say a thing about diff fluid!! But it did say for the auto trans fluid to be changed at 100,000mi and almost every manufacturer uses the same maintenance schedule on the trans fluid and the diff fluid. Best bet would be to call a Mercedes dealership and ask them about the maintenance schedule for diff fluid on a SLK320.

 

The differential is listed as being filled for life and maintenance free. People in the know on the Mercedes tech forums tend to disagree with that and service the differental as well as the automatic transmission at regular intervals.

 

Has anyone on the forum EVER had a problem with a differential with ANY automobile? We've had Chevys, Dodges, Chryslers, one AMC, one Nissan, a few Hondas and one Toyota. Most had a minimum of 150,000 miles when we sold them - never serviced a differential and never had a problem. Just curious.

 

Dude, I've blown up so many rear diff's it's not funny (but that happens when you tripple the power output and put slicks on it then drag race it). I've popped honda FWD diffs, Camaro rear ends, and DSM rear, center and front diffs. Lets not talk about axles and transmissions I have fried.

In this day and age it's east to make power, but it's still the art of putting that power to the ground that you must master!!

 

Scuba,
Don't know what year or milage your car is but I have seen other people on this forum check out their differential fliud and have found it to be in bad shape and changed it.
I would say ask a local Benz dealer or mechanic what they would recommend. I only have 20K on mine but plan on getting the tranny and dif serviced this coming summer by a Mercedes dealer if it doesn't cost me too much. Probably cheaper than a new dif or tranny. Never know how well a previous owner treated the car !

 

Stan, you can do it yourself and save a bunch of money if you can turn a wrench. Personally, I'm planning on a "Differential Day" soon where I'm going to do the fluid in the Crossfire as well as the S-Class at the same time.

Check out the DIY section of www.mercedesshop.com. There's a really good write up of how to change fluid in the rear differential as well as the transmission. The Crossfire uses the Mercedes 722.6 automatic transmission which is used by a whole bunch vehicles so don't be afraid of the article doesn't specifically deal with the SLK/R170 platform.


Edit: Here are a couple of links for you:

The transmission article is here: http://www.mercedesshop.com/Wikka/Trans7226Fluid

The differential is here: http://slk32.com/pages/diffoilchange/diffoilchange.html

And a really good write-up on general maintenance is here: http://www.benzworld.org/forums/r170...nce-guide.html

 

Anyone else have any more info on differential fluid change. From the link above it dosen't seem that hard.

 

I did it when I put the phantomgrip in. there is a drain plug on driver face. easy to do, I was into the case and wiped it down for good measure. WOODY Enjoy

 

A drain plug, cool, what about a filling plug? Is there one also on top? At what millage did you do your LSD swap and how did the fluid look?

 

This is good info to know.

I also have a 2005 wrangler...manual says change the diff fluid every 12,000...front and rear! BTW, no drain plug .

I will also be having a differential fluid changing party at my house....might as well include the x-fire....anyone have recommendations on a good fluid? How about synthetic diff fluid? Those of you that have replaced it in the x-fire, what did you use?

 

Car goes in circles and on the track now and then for 1/4. Just did a fluid check to see if the fluid had any tramp metal or sheen, looks good low milage 15k so far, rear at 13k.

Yes fill is higher up, Woody uses a metric allen key, DO NOT TIGHTEN much, they seem to get tighter over time and I scared myself getting it loose a while back, tight is not needed here. Woody enjoy..............

 

Especially if we are modding our cars!

 

Ok just went to the Dealer to have the oil change ($129) and they did their safety check and indicated that the rear diff was dirty. The car has 41,000 and is an '04. Wants to charge $189 to change it and $210 for cleaning the throttle body. Confused as to what to do..

As usual any advice would be greatly appreciated.

 

Of course it is dirty. It is a scare tactic but they are probably not lying. You can do it yourself for much cheaper. You will probably have to buy one tool which you can find at Sears. I used Mobil1 Synthetic.

If you were local I would do it for you for much much less and only take 30 minutes.

I can't comment on the TB since I have not messed with mine yet.

Check here for pics. Differential Service - CrossfireForum.org Gallery

James

 

Filled for life? This is the life of the warranty....right?

 

60$ for the synthetic gear oil from needswings and 30 minutes for the diy. 5$ for 2 cans of carb cleaner and an old rag. another 30 minutes. not confusing at all what to do!

 

I gave $11 a quart for Mobil1 Synthetic at Advance. You need 2 quarts to complete the job.

 

not the right oil for the wavetrac. i used the mobil 1 in my oem diff. my point was that 189$ for a diff oil change is crazy . even at the motul synthetic prices a diy is 1/3 the cost