You are getting into registered names of several slightly different trannies - and of course each manufaturerer makes the 'best' one...
There is a manual tranny. Need a clutch each time. The gears clatter a little when you shift. Better to be standing still between shifts. (Don't have to with practice tho...)
There is manual tranny with a meshing component that lets you shift (with clutch needed) between gears without the clatter. Can shift while rolling, but need the clutch.
There are trannies that allow you to shuttle between a forward & matching reverse gear without a clutch, but you need to clutch to change to a different forward or reverse gear - used for loaders.
There are trannies with different ranges where you need to use the clutch between the major ranges, but you can shift between different gears within a range without the clutch.
There are trannies that offer a hi/lo option in each gear, which does not need the clutch, but shifting between the regular gears requires the clutch.
And there are total powershift trannies where you can use the clutch if you want to, or you don't have to, just flick your wrist through the gears until you get to where you want to be - and back down again.
Then there are the hydro trannies.
Exactly what brand name means which tranny is a mystery to me. /forums/images/graemlins/smile.gif
Ford came out with one of the earliest powershifts in the '50s on the SoS trannies, they made the clutch pedal real small and called it an 'inching pedal' you used to hook up machinery, were just supposed to shift up & down otherwise.
--->Paul