Fatweed, I drove a 68 Freightliner with a 1674 Cat (270 HP) and an Eaton 15-speed. That's the 5X3 you're talking about. There was a definite technique to shifting that one, as any mistake in the power on/off and splitter switch movement would result in a false neutral, lots of grinding, and a SLAM into gear. My co-driver coasted about a hundred yards down the Grapevine hill in California before that rig found a gear, and about a week later it stranded me in downtown Salinas with a sheared-off input shaft to the rear end!
I was over a hundred miles from the company shop, so the boss loaded up the tool box in his pickup, and we overhauled the power divider in the middle of a graveled parking lot! No fun at all!
Jerry
