Could someone help identify my transmission? It's original in 1956 GMC 2-1/2 ton. Shift pattern goes like this:

2 4 R
I I I
-----------------
I I I
3 5 1
Direct

2 is low enough to take off easily, 1 is granny--
super low.
Thanks in advance.


Heavy metal worker--up to 4-inch plate.... If you can't cut it, burn it!