Here is the forum that Evan refers to:
https://talk.classicparts.com/

Here is the thread:
https://talk.classicparts.com/threads/transmission-trouble.22587/

The bright red/orange transmission (left, below) is the standard 1954 3100 3-speed, SM318
The unpainted transmission (right, two photos) is the HD 3-speed (3100 only in 1954), Borg Warner T89
Attachments
1954 SM318 3-speed.jpg (197.61 KB, 217 downloads)
T89 heavy duty 1954 3100 3-speed.JPG (196.18 KB, 219 downloads)