Thx for the reply. I understand about accessing the circlips in a standard open differential but the Wavetrac LSD unit puzzles me. It appears to be completely enclosed thus blocking off access to the circlips even with the differential cover removed. How is the axle retained and removed?
As for figuring out if axle modification is needed I plan to take a measurements of the distance between the flanges where the two piece axle joins together and see what the difference is between the W123 and W126. I've read one post that claims to have installed 1st generation W126 differential in a W123 and the W123 axles fit. Elsewhere I read that although the W123 differential housing is wider the splined axle stubs are more recessed so flange to flange distance is same with either rear end.
Thanks for reading this post.