I have tried looking via search functions on this and other forums. Postings seem split as to what weight is correct for E55 diff. I see 75/90 and 75/140 being claimed as "correct". Also have seen 85/90 listed. What is the current consensus as to the correct weight?

VIN WDBUF76J46A896801 (no P030 option that I can see)

 

When I did mine I came up with 85W-90. I suspect 80W-90 or 75W-90 would also work.

 

Use the MB bevo site.

 

When I had my rear diff fluid changed earlier this year, we used 85W-90 which is what is recommended.

 

i feel your pain. no one agrees on it honestly. i put it off for over a year and just a couple weeks ago went with mb 75-85. ECS tuning and a couple other sources have it on their sites as being the correct fluid for E55's so i finally just went with it.
https://www.ecstuning.com/b-genuine-.../001989330312/

This fluid falls under 235.7 specifications. i recall reading somewhere that this is the most up to date spec but i couldn't find anywhere in my owners manual what the original was.

 

OE is 75W-85W
001-989-33-03 12

https://www.pelicanparts.com/More_In...9-33-03-12-MBZ

 

When I go to FCP Euro they do not list the E55 for that oil: https://www.fcpeuro.com/products/mer...330310#fitment
This is one of the reasons I posted this. No clear answer across various sites.

 

When in doubt, go by your owners manual, or call the dealership. Just make a decision...

 

This. Stick with 235.0 fluid specification. If fuel efficiency is a concern, go with 235.7. 235.61 (75w140) spec fluids are for AMGs with factory LSDs.

The BeVo site, as mentioned above, is a great source for approved fluids per specification. Good luck!

https://bevo.mercedes-benz.com/beam.en.html

 

That's straight from the Dealer. I asked the Dealer, my Dealer mechanic and that is the specified oil from the MB dealer.

 

I wasn't trying to start anything or seem unappreciative. I finally looked at the owner's manual (it didn't occur to me that it would be in there for some reason). It is showing 85w90

 

I didn't take it that way, so no worries. I was just posting what the Dealer said and what they use.
I will be doing mine shortly and I will probably be using this.

https://www.amsoil.com/p/severe-gear-75w-90-svg/

 

Just like I said in post #4, 85W-90

 

You were right

 

That was was what was recommended when the car was manufactured. Manufacturers update fluids and make changes over time which they pass on to the dealers which may or may not be the case here. The difference between the two fluid weights we are discussing here is inconsequential. Many here have used 75W-140. You will be fine with whatever you choose.

 

But to be honest 75W-140 is what is recommended for LSD as it contains a friction modifier. But people run whatever they want to. But diff fluid needs to serve two purposes to lubricate and cool the ring and pinion.