To the best of my knowledge, all Roadragers have had a clutch brake, at least for the 30+ years I've been working with them. To stop the transmission input shaft from turning so 1st gear can be selected at a stop, the linkage is adjusted so the brake applies when the clutch pedal is pushed all the way down. It's only used at a dead stop. It's a lot easier to ease the shifter into 1st. as the vehicle comes to a stop, rather than fighting with it after it's completely still. Of course, on initial startup, etc., that might not be an option, or when a rig has been idling in neutral for a while.
Jerry
