Differential identification and lube on '87 300e

[Sopicki]

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