[ezzo]

Hi everyone,
For the benefit of other DIY folks, I am posting here the procedure for the 4Matic front differential oil change on my 2008 E300.

1- Warm up the car to operating temprature and drive around to get the diff oil to operating temprature too. This will make the extraction of the oil a lot easier.
2- Loosen front passenger side wheel bolts. Lift the car and remove front passenger wheel
3- Locate the fill/inspection plug. (refer to pictures)
4- Use an 8mm hex with extension to release the plug. (refer to pictures)
5- Find a small hose that is small enough to fit into the tight passage of the fill hole. The fill hole may look big enough, but you will need a hose thats outer diameter does not exceed 5mm (approx 1/4 inch) and is flexible enough to bend at the entry of the hole to go down to the bottom of the differential. I got a cheap siphon pump and cut a piece and attached it to my suction hose using electric tape. (refer to pictures)
6- Extract the oil by maneuvering the tube inside diff case. Try to move the thin hose around everytime to think you have extracted all the oil until you get almost 600ml out. (refer to pictures)
7- Before putting the new oil, I used the jack to tilt the car to the driver side (by raising the passenger side a bit more). I did this to add som extra oil such that when the plug is closed, the oil will be just in the middle of the plug, and not below it. That's just my OCD :grin, and you can skip this step.
8- This is a good time to change the brass washer on the plug (MB part number 007603-018101). For the fluid, I used the MB oil part number 001 989 33 03 12. (refer to pictures)
9- Pump the new fluid in and close the plug. (refer to pictures)

I did not use a torque wrench because it wouldn't fit in the tight space, but I think the spec is 14N.m.
*Note: If you want to use a different brand oil, use a reputable GL-5 spec oil. Do not use GL-4 in the diffs due to the high pressure of the hypoid gears. Refer to http://www.benzworld.org/forums/1450715-post2.html

 

[ps2cho]

I found that too flexible of a hose simply caved under the suction pressure...did your hose function fine?

I’d like to do mine again soon as I feel like I want to get more out this time and can’t hurt to dilute again

 

[jimbo1763]

I just had the differential fluid changed on my wife's 2006 RWD. My service guy said that MB is now recommending that the change be done every 40K miles or (I think he said) every two years.

 

[amosfella]

When I did that change on the 2004, I found that running the car to warm the diff up, and using a mityvac that had air compressor suction abilities was the best. I used a heat gun to warm the case of the diff further. That seemed to help.

 

[ezzo]

I found that too flexible of a hose simply caved under the suction pressure...did your hose function fine?

I’d like to do mine again soon as I feel like I want to get more out this time and can’t hurt to dilute again

The one I used from the cheap siphon pump did not collapse under suction pressure. you have to try out different types. I started with the small tube of a cheap plastic spray bottle. But it was too narrow, it would have taken an hour to get that thick oil out.

 

[ezzo]

I just had the differential fluid changed on my wife's 2006 RWD. My service guy said that MB is now recommending that the change be done every 40K miles or (I think he said) every two years.

Now that I have done it a couple of times already, I would not mind doing it every year to keep the drive train smooth. I wish the transfer case was as easy. I am still trying to figure out how to do it without removing the cross member!

 

[ezzo]

When I did that change on the 2004, I found that running the car to warm the diff up, and using a mityvac that had air compressor suction abilities was the best. I used a heat gun to warm the case of the diff further. That seemed to help.

A heat gun? That's a good idea. I never thought of that.

 

[amosfella]

A heat gun? That's a good idea. I never thought of that.

In the 2004, there's a cross member that sits in a perfect position to wedge the heat gun in when you take the pan off to drain the engine oil. I started the mityvac, and the heat gun, and went on with draining the other oils while the thing sucked.

With the transfer case, I found it really easy to do simply by using an impact. Took more time to drain than to take it apart and put back, including torquing the whole way along. Use an impact on the plugs, even if you have to use all kinds of funny extensions and wobbles. The top one was the hard one. Open it first.

With the proper extensions, you might be able to get it open without taking the cross member out. You'd need something for the oil to run down to keep it from collecting in the cross member... I've done that on a quad. I took a windshield wiper bottle, cut a square out of it, folded it into a trough with a bit of heat, and used that to get the oil out of a quad without spilling oil on the frame. Wish I had thought of that before I opened the engine oil drain plug on the 2004, even as a deflector to keep the oil from getting on the frame. Next time.

Oh ya, one of those 37L rubbermaid tubs are great for changing oils where there's a lot of oil. The windshield washer bottles with holes cut in a side are great for rear diffs, transfer case, etc. Done right, one can practically drain the whole car at once...

 

[ezzo]

Thanks, @amosfella for the details. However, I don't find it easy to visualize what you did exactly. Do yo have some pictures that you can share or some instruction pages from the MB manual? I deffinitely don't want to remove the cross member under the TC and I don't want to mess up with the drive shaft flex desk, etc. I will also be working under the car in the garage; so, I don't want to jack up the transmission if the cross member and mount are removed and want to keep it the safest in terms of avoiding things to fall over me. My local MB in Vancouver quoted $250 for the job (including the oil) but I just prefer to avoid paying them any cent. But again, if paying $250+tax will avoid having me killed under my car, then I'll just do it! :-/

Conclusion, if there was a way to get to those transfer case fill/drain plugs without removing the cross member, I would love to hear more details about it. I tried to search the forrum for any thread that talks about this, but did not find any.

Thanks!

 

[amosfella]

Thanks, @amosfella for the details. However, I don't find it easy to visualize what you did exactly. Do yo have some pictures that you can share or some instruction pages from the MB manual? I deffinitely don't want to remove the cross member under the TC and I don't want to mess up with the drive shaft flex desk, etc. I will also be working under the car in the garage; so, I don't want to jack up the transmission if the cross member and mount are removed and want to keep it the safest in terms of avoiding things to fall over me. My local MB in Vancouver quoted $250 for the job (including the oil) but I just prefer to avoid paying them any cent. But again, if paying $250+tax will avoid having me killed under my car, then I'll just do it! :-/

Conclusion, if there was a way to get to those transfer case fill/drain plugs without removing the cross member, I would love to hear more details about it. I tried to search the forrum for any thread that talks about this, but did not find any.

Thanks!

That was just a supposition from what I remember from when I did it on the 2004. Mind you, mine could be different underneath than yours. If you have your entire car sitting on jackstands (like I did. Also note these were 12 ton a piece jackstands with large bases), having a rolling floor jack underneath it when you remove the cross member is not that dangerous. You're only lowering it an inch, so no need to worry about the flex disk.

While I think that it could be possible to change the TC oil without removing the cross member, I think the first time will be very difficult. It's almost impossible to see in there without taking it off.

A lot of your danger will be limited by not twisting on things. So, that's why I recommend using an impact to remove the plugs. The top one will likely be a bugger. Also, the plugs are much less likely to strip out the head if one used an impact instead of a breaker bar. A flexible extension will be a great tool (they have these at princess auto). I couple or 3 wobbles and a few extensions of different lengths will help. As I recall, I had 3 feet worth of extensions and wobbles on mine to get the top plug out. It was routed up over top of the exhaust pipe. You can go to home depot and rent a cordless impact for the job, if you don't have an impact available. IIRC, you'll need 14, 15, 16, 17 mm sockets.

I've only done the job once, and it was over 5 months ago, and I've had a lot of creative solutions jobs since, so I might not be remembering everything correctly.

I look at it this way, If I do the job myself, I can put the money saved into tools for the job, and that can bu used for other jobs. Keep an eye on kijiji, etc for tools, or rent the ones you can't afford at this time. The hardest part will be getting the new oil back into the transfer case. Get a good oil syringe. Don't buy a cheap one. The cheap ones won't pull the oil up.

 

[amosfella]

Also of note, buying a allen head socket from snap on may very well be worth the investment. For some reason, those sockets seem less likely to strip out the plug heads.

 

[ezzo]

That was just a supposition from what I remember from when I did it on the 2004. Mind you, mine could be different underneath than yours. If you have your entire car sitting on jackstands (like I did. Also note these were 12 ton a piece jackstands with large bases), having a rolling floor jack underneath it when you remove the cross member is not that dangerous. You're only lowering it an inch, so no need to worry about the flex disk.

Wow... That's an encouraging set of details. I will have to get the jackstands with large bases. I have only a pair of 3-ton stands (from princess auto)to hold the car up from one side only. I better get another pair, probably of a heavier grade too.
So you are saying that if I remove the cross member, I won't have to hold teh transmission and TC with a jack? I saw a Youtube video and the guy was supporting the TC with a jackstand @1:04 [ame]https://youtu.be/IXfQ8h8TvSM?t=1m4s[/ame].

While I think that it could be possible to change the TC oil without removing the cross member, I think the first time will be very difficult. It's almost impossible to see in there without taking it off.

Once I securely hold the car off the ground, I will endeavor to reach to the fill plug without removing the cross member.

A lot of your danger will be limited by not twisting on things. So, that's why I recommend using an impact to remove the plugs. The top one will likely be a bugger. Also, the plugs are much less likely to strip out the head if one used an impact instead of a breaker bar. A flexible extension will be a great tool (they have these at princess auto). I couple or 3 wobbles and a few extensions of different lengths will help. As I recall, I had 3 feet worth of extensions and wobbles on mine to get the top plug out. It was routed up over top of the exhaust pipe. You can go to home depot and rent a cordless impact for the job, if you don't have an impact available. IIRC, you'll need 14, 15, 16, 17 mm sockets.

Noted.

I've only done the job once, and it was over 5 months ago, and I've had a lot of creative solutions jobs since, so I might not be remembering everything correctly.

I look at it this way, If I do the job myself, I can put the money saved into tools for the job, and that can bu used for other jobs. Keep an eye on kijiji, etc for tools, or rent the ones you can't afford at this time. The hardest part will be getting the new oil back into the transfer case. Get a good oil syringe. Don't buy a cheap one. The cheap ones won't pull the oil up.

That's my objective to, to save the money towards tools and eventually save money, period. I've a good pump (in the pictures in my original post) from Lordco, which is quite sturdy and reliable.

Thanks a lot @amosfella for this! I will post the results when I get this job done!

 

[ezzo]

Also of note, buying a allen head socket from snap on may very well be worth the investment. For some reason, those sockets seem less likely to strip out the plug heads.

I agree. I got a set of allen head sockets from Canadian Tire.

 

[amosfella]

Wow... That's an encouraging set of details. I will have to get the jackstands with large bases. I have only a pair of 3-ton stands (from princess auto)to hold the car up from one side only. I better get another pair, probably of a heavier grade too.
So you are saying that if I remove the cross member, I won't have to hold teh transmission and TC with a jack? I saw a Youtube video and the guy was supporting the TC with a jackstand @1:04 https://youtu.be/IXfQ8h8TvSM?t=1m4s.

Not quite. I used the jackstands to hold the car off the ground as if it was on a lift. I used a rolling floor jack with a soft wood 2x4 on it to support the transfer case when I took the cross member out. Then I could control how much I lowered the transfer case, and get it back in easily.

IMHO, the 6 ton pro point jackstands should be a good option. Check kijiji. I had 12 ton ones as I was using them for brake jobs on semi trailers and trucks. I had to use the 12 ton ones with the adjustable arms removed as my jack was just a little too short to get the car on top of the stand. If you can find a few sets of 12 ton ones, go for it.

Here's the best pic I have of how I set it up. I jacked up the front end first with the jack under the center jacking point. If you only get one set of really heavy/wide base jack stands, I'd put them under the front. Then I jacked up the rear using the rear diff as a jack point and set the jack stands under it. You could easily use the lighter set of jack stands under the rear. Hope this helps.

2018-04-12_12-38-25 by wolverine00089, on Flickr

 

[ps2cho]

You need access to the very top fill port. Filling via the inspection port ends up being underfilled based on the way internal design. Its an extra 10mins to do it right.

 

[ezzo]

You need access to the very top fill port. Filling via the inspection port ends up being underfilled based on the way internal design. Its an extra 10mins to do it right.

So, this means also removing the mount and bracket. So I should fill the fluid from the fill port until it starts to drip? sounds like the TC is underfilled by a substantial amount in your car @amosfella!

On another note, in your opinion, how can the inspection port be so low compared to the fill port, @ps2cho? If someone needs to inspect from there, a lot of fluid can come out!

 

[amosfella]

So, this means also removing the mount and bracket. So I should fill the fluid from the fill port until it starts to drip? sounds like the TC is underfilled by a substantial amount in your car @amosfella!

On another note, in your opinion, how can the inspection port be so low compared to the fill port, @ps2cho? If someone needs to inspect from there, a lot of fluid can come out!

On the 2004, there was no top port that I could find. I filled the TC till it was to the top of the inspection port, then filled another 200 ml into the syringe, wrapped paper tower around the syringe hose and jammed it all in, and got the plug in very quickly. I lost maybe 20 ml doing it that way. There were just a few drops on the floor.

Thanks for your concern, though. I've always jammed extra fluid into diffs, TCs, and other geared boxes. I like to have the plug partially if not fully covered, as it makes taking the plug out later much easier.

 

[ps2cho]

Because AFAIK you will be 200-300ml underfilled by using the inspection port. The fluid capacity is about 650ml or so, but if you drain after filling via inspection port, you'll suddenly find you only put in ~400ml. Something about an air lock, hence why MB has a top fill port.

I originally filled via inspection, realized the mistake and went back and redid it correctly.