Differential identification and lube on '87 300e - PeachParts Mercedes-Benz Forum

Sopicki · #1 02-27-2007, 12:59 AM

Hi folks,

I want to change the oil in my differential since my car is 20 years old and since I have no history on the car I can only assume it is the original oil.

I know that if it is a limited slip diff it should have a tag bolted on to the side of the diff., but the absence of evidence is not evidence of absence! My diff does not have a tag. I have 2 clues that make me think I MAY have a limited slip diff. 1) With the car off the ground, if I rotate one rear wheel the opposite wheel turns the same way. 2) My wife was following me in our Volkswagen and said that both wheels were throwing snow when starting off in a recent snow storm. How do I determine for SURE?

I'm aware that MB calls for different lubricants for the different differentials. The 300e Bible says synthetic lubes are not approved. I've always used Mobil 1 75W-90 in my strait diffs. What kind of lubes do you folks use for either type diff?

Thanks as always.

Bob Kopicki
'67 TR-4a
'76 GMC C-15
'85 XJ-6
'87 300e
'97 VW Cabrio

#2 02-27-2007, 07:01 AM

Safely raise both rear wheels off the ground and turn one while observing the other. If both wheels go the same direction it is an LSD, if they turn opposite directions it is an open differential. I am VERY surprised that both wheels turn the same direction on yours. I have never seen a 124 with an LSD. If it is you will need to add the friction modifier when you change the lube. Put only enough of the friction modifier in it to keep it from clicking in a sharp turn.

I am not surprised that Stan or whatever his name is, would say that synthetics are not approved. He used to seem like a very knowledgable guy until he lost his credibility by putting out that Bible book. All it amounts to is a compilation of various facts and diagrams from factory MB material. As far as I'm concerned he lost credibility BIG TIME when he put out that book. Before the book he seemed like the authority and after the book he just seemed like a robot that could read MB material.

I believe that reality is that because synthetic gear lubes were uncommon at the time of the 124 design, MB had not yet taken a position. Since MB had not officially issued anything on the subject, the robot had nothing from MB to refer to, so he printed that non committal statement about synthetic gear lube because he was totally lost with no thinking power of his own.

Make sure that you think about how you will manage to get lube in once it is empty. I have a pump on a five gallon can of lube. You probably can use squeeze bottles. Place a drain pan underneath and REMOVE THE TOP FILL PLUG FIRST! This is so that you know for sure that you can remove it so you will be able to refill it. Then pull the drain plug and drain. I think it is a 14MM socket head, commonly known as an Allen.

Good luck,

mbdoc · #3 02-27-2007, 08:04 AM

You don't have to worry that that diff is limited slip...never available on USA models..

Starting in 1991 a few diesels had ASD as an option in the USA, but not a single gas powered one.

Sopicki · #4 02-27-2007, 10:03 AM

Larry and Doc, thanks for your replies.

Like I said, I have no history on this car. Without a doubt the rear wheels turn in the SAME direction when I have the car off the ground. If the direction of the wheels turning is the litmus test that proves one way or another the presence of a LSD, I would have to say there is a LSD in my car regardless of whether LSD's were or were not supplied as original equipment.

I've never owned a LSD and know very little about how they work or what lubricants they use. Would I be right to assume that putting straight gear oil in a LSD could cause damage to the LSD, but putting the correct LSD lubricants into an open diff would probably cause little damage? I'm just afraid that without KNOWING which diff. I have I could do more bad than good by changing the oil with the wrong lube.

If we assume a LSD is in the car, Larry are you saying I can use regular or synthetic (which I prefer) gear oil and then add a friction modifier. I have no baseline as to how much of this modifier to add. Where do I start? Enough to keep it from clicking? Is there something that is pre-mixed?

Lots of questions, sorry.

Bob

mbdoc · #5 02-27-2007, 10:08 AM

Really bad that you have incorrect info...

Many differentials will allow both wheels to turn...You don't have a LSD in that car.

Any good 80W/90 hypoid will work.

#6 02-28-2007, 07:33 AM

If the car were mine I would be using regular hypoid gear lube because that is what I have on hand. If I had a hankering to use synthetic, however, I would not hesitate.

The Doc is correct as always, sometimes open diffs will turn both wheels the same direction.

Hirnbeiss · #7 02-28-2007, 02:56 PM

Quote:

Originally Posted by M.B.DOC

Really bad that you have incorrect info...

Many differentials will allow both wheels to turn...You don't have a LSD in that car.

Any good 80W/90 hypoid will work.

Why do you say that? ASR (and ASD) was available as an option on the W124, and I know my 95 E320 had it. It was probably an option determined by engine size, and 3.0 liters for the Europeans is of gigantic proportions.

Follow up: I think I found one source of the confusion. You probably have ASR, a Limited Slip Differential. It is only the ASD, or locking differential, that has the tag on the outside. Both require the same oil, though. Source: WIS

mbdoc · #8 02-28-2007, 04:11 PM

LSD means a mechanical set of clutches in the differential.

AS I posted the only USA W124 chassis other than 4-matic cars that have a mechanical locking differential was the W124.128 300d 2.5 with ASD & the 1995 E300D W124.131 chassis with ASD!

ASD= Automatic Sperry Differential special order option from 1991-95 on diesel & low torque gas powered cars.

ASR never includes a locking differential..that traction system is torque reduction & brake lock-up

Even the mighty 500E (E500) didn't have an LSD but used electronic traction control instead...

"Hirnbeiss" your car doesn't have a LSD either!

david s poole · #9 02-28-2007, 05:08 PM

is it possible that you have a euro import where you could order just about anything.there are sites that will list your vin # and all the options that the car was built with.

Hirnbeiss · #10 02-28-2007, 07:20 PM

Quote:

Originally Posted by M.B.DOC

LSD means a mechanical set of clutches in the differential.

We all know that

. What I thought was that ASR also had a clutch pack based on the WIS drawing, but I checked again and it was ASD that had the clutch pack. My bad

. MBDOC is right again

.

Also, ASR was first introduced in '87. I think the giveaway you have it is the flashing triangle in the dash when you start to spin wheels.

mbdoc · #11 03-01-2007, 07:53 AM

ASR came to the USA in 1991...that is what I posted.

hanno · #12 03-01-2007, 11:32 AM

Can this be view from another angle? Assuming

that the introduction of a friction modifier or the special limited slip fluid from MB causes no harm, then you are covered whatever the differential is (or isn't).

mbdoc · #13 03-01-2007, 11:50 AM

Correct & MB number 001-989-17-03-10 is that fluid.

Cervan · #14 03-31-2007, 04:34 PM

you could allways do the goodo ld rev the engine into the red and then dump the clutch. if you leave one line of rubber then you have an open diff if you leave two then you have lsd.

Abadjay · #15 05-31-2009, 01:48 AM

I saw this (picture 1) at Walmart trying to look for Mobil 1...unsuccessful, but would like to know if anyone has had success or failures with this "Supertech" brand lube.

I was planning on changing the fluid to that in the rear differential, but wouldn't mind spending for good synthetic brands if need be.