After some searching through Stretch's and my threads I finally found a picture which had the location visible.

You can see the machined flat just to the right of the shiny locking tool.


This is a closeup of the tool, but you can see just to the right the markings on the flat. The first marking is the "A."


Sometimes you do have to clean that surface off. The box in the picture was completely stripped of grime and wasn't repainted before it was installed. I say this because the markings are shallow enough that paint can obscure them.

__________________
Onus probandi incumbit ei qui dicit, non ei qui negat

I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]