Didn't the W116 6.9 use a LSD? FYI There is one on eBay, starting bid $500 I believe its in the NE (New England/NorthEast) area somewhere, I came across it last night. Parts car category.
The LSD differential would I think be a 2.65 ratio, you just can't find that LSD when you want one!

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'95 E320 Wagon my favorite road car. '99 E300D wolf in sheeps body, '87 300D Sportline suspension, '79 300TD w/ 617.952 engine at 367,750 and counting!