hi mick53, 5 of the 6 trucks i have came with PTO driven hydraulics for the bed lift, 3/4 ton to 2.5 ton, all similar looking pumps that are inside their reservoirs (black box with PTO input and a up/down lever) they were not factory, but the trucks were designed with installing a bed lift kit in mind many trucks would get the lift installed by the dealer so you could start using it as soon as it was home
the pump isn't fast, but it's quite tight, if you don't stop it you can hear the engine RPM drop very sharply as the rams bottom out. if you forget the PTO on and go for a fast drive i was told you could pop the PTO housing off the transmission and be left with broken gears and castings.
the PTO is a lot more power than any belt can output, at idle speeds it looks to be turning a about 100 rpm or so, you can always pull out the throttle to make it spin faster, but that's never necessary with the pumps on my trucks full over load of gravel goes up at any RPM, just goes up slower -s
