W116 W123 W126 R107 Differential Interchangeability

[Hellcat94]

So a W123 Diff and a W126 diff are not interchangeable, but a W116 diff looks alot like a W123 diff, are they interchangeable? What about the R107?

[Frank Reiner]

Hc:

There are two sizes of diffs for the models that you mentioned: 185mm, and 210mm ring gear diameter.
From 1968 to 1985 all (both sizes) mounted to the subframe with the same stud pattern. From 1986 onward, W126 & R107 had a different mounting to the subframe and frame floor.

[Hellcat94]

So will a W123 differential fit to a W116 with enough length to reach the driveshaft, and also not put it at a vague angle?

[NZScott]

I believe all the models mentioned above have near identical rear subframes, so diffs being the same will mount fine. You just need to use the correct axles.

Driveshaft yokes are a different story however, you may have to swap that over. A quick forum search should reveal all you need to know in that regard