Here is an interesting read. It refers to the corvette C1 which is a similar box to an AD box. Seems there was a technical bulletin that addresses this in 1957.
https://www.corvetteforum.com/forums/c1-and-c2-corvettes/2173438-c1-steering-gear-lubricant.html


1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration