SL/R231: Rear diff capacity?
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Joined: Feb 2021
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From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
You will have a internal 14mm hex instead of a bolt head for drain/fill plugs. Also your diff can take 75W-90 (without modifier) I believe Mercedes’ recommends 85W-90 (Castrol)
Yes both drain and fill plugs. Mobil 1 is easy to find and works well.
https://mbworld.org/forums/sl-class-...il-change.html
Last edited by crconsulting; Mar 21, 2022 at 07:04 PM.
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Joined: Dec 2015
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From: Hagerstown MD
2015 SL400; 2019 X5M40i
ram_g posted a nice tutorial with pics. While he has a LSD, the capacity and housing are identical. Just buy 2L
You will have a internal 14mm hex instead of a bolt head for drain/fill plugs. Also your diff can take 75W-90 (without modifier) I believe Mercedes’ recommends 85W-90 (Castrol)
Yes both drain and fill plugs. Mobil 1 is easy to find and works well.
https://mbworld.org/forums/sl-class-...il-change.html
You will have a internal 14mm hex instead of a bolt head for drain/fill plugs. Also your diff can take 75W-90 (without modifier) I believe Mercedes’ recommends 85W-90 (Castrol)
Yes both drain and fill plugs. Mobil 1 is easy to find and works well.
https://mbworld.org/forums/sl-class-...il-change.html
Any reason to install new plugs or just use the same ones? Never thought about Teflon tape.
How about Motul GL5 85W90 gear oil?
MBWorld Fanatic!
Joined: Feb 2021
Posts: 1,419
Likes: 739
From: Nor-Cal
2020 GLC300 -2014 Sl550 - 1997 SL600
The Motul GL5 should be fine. 👍
Last edited by crconsulting; Mar 22, 2022 at 12:21 AM.
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R231 SL63 & R129 SL500
See my additional post I made just now in my other diff oil change thread. While I reused the plugs in my R231 I chose to replace the plugs in my R129 because they were heavily rusted. I’d recommend taking a peek at your plugs before you decide. ‘Course my R231 is a 9 year old car that has spent its life in Texas, while my R129 is 24 years old and lived in Ohio and Indiana and who knows where else nasty place before I rescued it! 
Thread Starter
MBWorld Fanatic!
Joined: Dec 2015
Posts: 1,640
Likes: 524
From: Hagerstown MD
2015 SL400; 2019 X5M40i
See my additional post I made just now in my other diff oil change thread. While I reused the plugs in my R231 I chose to replace the plugs in my R129 because they were heavily rusted. I’d recommend taking a peek at your plugs before you decide. ‘Course my R231 is a 9 year old car that has spent its life in Texas, while my R129 is 24 years old and lived in Ohio and Indiana and who knows where else nasty place before I rescued it!
https://www.fcpeuro.com/products/mer...des-3529970032
