SL55/63/65/R230 AMG: DIY : SL55 Rear Axle fluid change
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03 SL55, 07 Acura MDX
DIY : SL55 Rear Axle fluid change (Rear Differential)
It was about that time for the Merc to get some attention so I decided to change up all my fluids, I've searched and searched all over on several DIY's (Rear axle among them) and came up with nothing, so I figured i'd tackle the job myself and here it goes.
The rear axle is a pretty straight forward and easy job to handle so no worries people, on a scale of 1-10, i'd give this one a 3.
Tools you'll need are:
1) Socket wrench (preferably 1/2" drive)
2) 14mm Hex bit socket
3) Adjustable wrench
4) Fluid transfer pump (you can pick one up at your local auto parts store, or walmart)
5) 1.5 Qts of Hypoid Gear Oil, Owner's Manual has it listed as SAE 85 w 90, Apparently it's a hard grade to come by so I stuck with 80 w 90, it's close enough.
14mm Hex, My local autozone had the 3 piece bit set for $12.99![naughty](https://mbworld.org/forums/images/smilies/naughty.gif)
http://www.autozone.com/autozone/acc...questid=230227
![](http://farm8.staticflickr.com/7355/10216907175_241ce37e15.jpg)
Fluid Pump from any walmart or auto parts store
http://www.walmart.com/ip/Mercury-Qu...-Pump/17165291
Let's get started, first you'll need to jack up your vehicle and support it two Jack stands. once that's done the rest is pretty straight forward, You'll need to find your Rear Axle which will be located right btwn your two rear wheels. Next locate your Drain and Fill plugs, Drain plug is located on the passenger side of your Rear Axle, and the Fill plug is located on the drivers side. Before you attempt to drain any fluids I would first recommend you spray both bolts with WD40 to help loosen the bolts and make the job a bit easier, let site for 10-15mins.
Step 1:
Begin with removing the Fill plug. Why the fill plug? Easy, if you can't break loose the fill plug, how do you intend on refilling the axle with fluid once you've already drained the fluid?![crazy](https://mbworld.org/forums/images/smilies/crazy.gif)
![](http://farm3.staticflickr.com/2850/10217883336_4ab84647f8.jpg)
Step 2:
Now that the Fill plug has been loosened, Remove the Drain plug and let the fluid drain, Space is pretty tight so I had to improvise, I used the 14mm Hex bit with a wrench to get the bolt open.
I have no idea when or even if my vehicle was serviced before, but wow was my stuff bad, not only that but just a littler over 1qt was drained. Not good!
![](http://farm4.staticflickr.com/3682/10216815404_f114b593fe.jpg)
![](http://farm8.staticflickr.com/7457/10216907635_0664e48da4.jpg)
Step 3:
Clean both Drain and Fill Bolts and reinstall the Drain plug
Step 4:
Refill with new fluid by using the fluid pump and inserting the hose into the Rear Differential and pump until 1.5 Qts has been added, you'll also notice fluid start to drip out once the Differential has been filled completely. Reseal the bolt, wipe down the area, and your done!
![](http://farm8.staticflickr.com/7343/10217017183_92f0ee7076.jpg)
![](http://farm8.staticflickr.com/7342/10216907375_0f989c8cc0.jpg)
Now tighten everything back up, lower the car and go have some fun
. You just saved yourself a couple of Hundred bucks by avoiding the stealership once again
! All in all the job only takes about 30-40mins from the time you start jacking, till the time you lower the car.
The rear axle is a pretty straight forward and easy job to handle so no worries people, on a scale of 1-10, i'd give this one a 3.
Tools you'll need are:
1) Socket wrench (preferably 1/2" drive)
2) 14mm Hex bit socket
3) Adjustable wrench
4) Fluid transfer pump (you can pick one up at your local auto parts store, or walmart)
5) 1.5 Qts of Hypoid Gear Oil, Owner's Manual has it listed as SAE 85 w 90, Apparently it's a hard grade to come by so I stuck with 80 w 90, it's close enough.
14mm Hex, My local autozone had the 3 piece bit set for $12.99
![naughty](https://mbworld.org/forums/images/smilies/naughty.gif)
http://www.autozone.com/autozone/acc...questid=230227
![](http://farm8.staticflickr.com/7355/10216907175_241ce37e15.jpg)
Fluid Pump from any walmart or auto parts store
http://www.walmart.com/ip/Mercury-Qu...-Pump/17165291
Let's get started, first you'll need to jack up your vehicle and support it two Jack stands. once that's done the rest is pretty straight forward, You'll need to find your Rear Axle which will be located right btwn your two rear wheels. Next locate your Drain and Fill plugs, Drain plug is located on the passenger side of your Rear Axle, and the Fill plug is located on the drivers side. Before you attempt to drain any fluids I would first recommend you spray both bolts with WD40 to help loosen the bolts and make the job a bit easier, let site for 10-15mins.
Step 1:
Begin with removing the Fill plug. Why the fill plug? Easy, if you can't break loose the fill plug, how do you intend on refilling the axle with fluid once you've already drained the fluid?
![crazy](https://mbworld.org/forums/images/smilies/crazy.gif)
![](http://farm3.staticflickr.com/2850/10217883336_4ab84647f8.jpg)
Step 2:
Now that the Fill plug has been loosened, Remove the Drain plug and let the fluid drain, Space is pretty tight so I had to improvise, I used the 14mm Hex bit with a wrench to get the bolt open.
![EEK!](https://mbworld.org/forums/images/smilies/eek.gif)
![](http://farm4.staticflickr.com/3682/10216815404_f114b593fe.jpg)
![](http://farm8.staticflickr.com/7457/10216907635_0664e48da4.jpg)
Step 3:
Clean both Drain and Fill Bolts and reinstall the Drain plug
Step 4:
Refill with new fluid by using the fluid pump and inserting the hose into the Rear Differential and pump until 1.5 Qts has been added, you'll also notice fluid start to drip out once the Differential has been filled completely. Reseal the bolt, wipe down the area, and your done!
![](http://farm8.staticflickr.com/7343/10217017183_92f0ee7076.jpg)
![](http://farm8.staticflickr.com/7342/10216907375_0f989c8cc0.jpg)
Now tighten everything back up, lower the car and go have some fun
![drive](https://mbworld.org/forums/images/smilies/driving.gif)
![naughty](https://mbworld.org/forums/images/smilies/naughty.gif)
Last edited by HFELIU; 10-13-2013 at 02:27 PM.
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jvakos (12-09-2020)
#5
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Join Date: Jul 2012
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03 SL55, 07 Acura MDX
I've never seen the Rear DIfferential on a CLS55, But it's pretty much the same standard routine for changing most Diff fluids. Seeming as it's a Benz I'd pretty much guess it'll be the same fitment for tools.