Here is what I can add. I am not making this up.

There were two 5-speeds made in the 1970's, the G76/18/5 and the G76/27/5. I believe that they were the same except for minor differences in the internal gearing. They are physically different from the 4-speeds only in their length to accomodate the .87 overdrive unit on the back.

I have had a /5 and and /4 unit sitting side-by-side on my workbench, and this is the basis for my statement above.

I believe that these units will bolt up to any bellhousing/engine that took the equivalent "/4" box. You would need to find linkage and shorten the driveshaft.

But I am not sure about your assessment of the M110. Some time in the 1980's, Mercedes started using a different 5-speed in the 201's and 124's and some 110's. I personally saw one in a 1985 280SL that I almost bought. It can be identified quickly by the little fins on the bottom of the case. I do not know if this trans takes the same bellhousing/clutch stuff as the earlier units.

So bottom line, I think an earlier "/5" would work in your car, and maybe the later unit if they didn't change the bellhousing.

It's very hard to get information on the earlier 5-speeds in the US because they were not officially imported here.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe