I’m going to change my rear differential fluid on my 2008 E320 Bluetec. The manual that came with car says use 85W90 fluid. FCP Euro says 75W85 or 85W90. Big price differences between Mercedes oil and Red Line and Liquid Moly. Any opinions out there about fluid weight and brand differences? Thanks

 

I've got the exact same car as you and I use Mobil 1 75w-90 gear oil. Smooth and quiet.

 

Thanks. I have seen that mentioned too. I trust that brand. Interesting that it spans 15 degrees of viscosity compared to some of the other products which span only 10. Glad to hear from another pre-DEF OM-642!

 

I love my pre-DEF OM642! This is my second W211 but my first diesel. Had a few minor issues when I got it but now that it's sorted it's a great ride.

I also used the Mobil 1 75w-90 in my 05 E320 without issue. The manual for both these cars stated 85w-90 but Mercedes must have updated the spec because now they call for 75w-85 as per this: https://operatingfluids.mercedes-benz.com/sheet/231.1

I figure the Mobil 1 is a good option because it covers the entire viscosity range from the manual and updated spec, and it's Mobil 1.

 

Is the diff limited slip? If not, you're better off without the extra additives.

 

Mine is not. I was wondering about that actually. Do you have any other recommendations?

 

Mercedes doesn't make it easy... Does your car call for 235.7 spec oil? Good luck finding an oil in the US that meets that spec other than the dealer. Last time I did it I was able to get some from Febi Bilstein, probably at FCP Euro. If you're not concerned about having that approval, I'd go with any name brand GL-5 synthetic that is either 75W-85 or 75W-90, without limited slip additives. The lower second number is probably for fuel economy claims. There wouldn't be any significant difference in lubrication.

[Edit] I did not get it from FCP. Can't say where. FCP does offer Redline and says it meets the 235.7 spec

 

For my W204 I use the Febi 75W-85 which meets the specific spec for front and rear diff on my car. Not sure which specific MB spec is for yours.

I was able to find it locally from an online diesel parts website that has free pickup at the warehouse a few miles from my house.

I see FCP has it also for $29/quart.




They have the Fuch's that says it meets similar specs, but not all.