Great video Skyraider! I cut my teeth and a few transmission teeth on Mack two stickers. I took my class A road test in a 1957 single axle B model Mack, with a 13 speed triplex, pulling a 40' flat. I was two years older than that truck! At the time I was doing regional household goods moves with another driver in a B model, but with a 10 speed duplex. He suggested I go with the triplex for my road test because it was easier to shift, especially in town. The duplex required a compound shift every other shift.
The B model in the video has a triplex transmission, either a 13 speed or 15 speed. The only difference between the two is that with the 13 you go from 4th high directly to 5th on the main box, no splitting 5th gear. The stick closet to the driver is the 3 speed auxiliary box and the other is the 5 speed main gear box. You start out in first on the main box and split each gear with the 3 speed auxiliary. The tricky part comes when you make a compound shift. A compound shift requires shifting the main box to the next gear and then shifting the aux. box back to low without losing too much engine speed. If you miss the shift, and this can happen on a hill, its a mad scramble to get the main box back to the original gear and the aux. back to where you can pick it up again.
The 10 speed duplex is set up with the stick for the 5 speed main box closest to the driver and the 2 speed auxiliary stick on the outside. As mentioned, the duplex requires a compound shift every other shift making it slightly more difficult to shift for a rookie.
I'd give my left...ah, I'd easily pay $100 to take a quick spin in a B model with two sticks or an F, R or U model. I think I could still shift one, kinda like riding a bike. It sure would be fun.
