when is a 5 x 4 not a 5 x 4 ?

[greywuuf]

kinda new to the " big" truck thing, driven a few 5 speeds with 2 speed axles, my unimog has a 5 speed and a 3 speed aux but never an air shift or a road ranger. I am looking to buy a particular truck in my area, and it has a 5 speed with a 4 speed brownie. I understand running one transmission into a second one, but I gather that is not how road rangers and such work. additionally when I google and you tube 5x4 transmission or twin stick ... I seem to come up with a lot more on the Big truck trannies and not so much on the "brownies"

So is my shift pattern just going to depend on what two transmissions I have and where the gear overlap occurs ?, or was there a "standard" pattern that chevy adhered to ? given the time and some way to turn the transmission ( like remove it from the engine) I could determine each individual gear ratio and work out the technically correct pattern, but I was hoping to not have to go to that extreme right away.

Dan in the frozen North