All W124's in the USA with the DOHC M104 engine use the 2.65 diff, which I believe is MY 1993-1995.

Find one with an instrument cluster and the driveshaft, to swap and you'll be set.

So if you have access to a 1994 W124 wagon's diff, driveshaft, and speedo, you're set.

The 400E's use I think a 2.24 diff, but it is 4-bolt configuration, with different splines, and a different cover.

:-) neil