ABS
ABS
When I swapped rear ends from 3.07 to 2.88, I used a 1985 300SD rear end that had been equipped with diff mounted ABS. The rear end was identical in all other dimensions and fit the 123 no problem, but the sensor was on the passenger front of the housing reading off a speed sensor on the pinion shaft. I dont imagine that would be too easy to swap. Maybe you could find one of these rear ends in a junkyard.
Ironically, I removed the sensor and plugged the hole.