This is A DUAL SYSTEM WITH 12 VOLTS SUPPLYING POWER TO HYDRAULICS OR A ONAN 6.5 GENSET WITH A HYD.PUMP PIGGYBACKED WHICH ALSO POWERS UNIT . I traded for this 90Ford ONE OWNER IN GREAT SHAPE 96,000 MIBUT ONLY THING IS I HAVEFOR THE VERSALIFT no book cant find one online,Or a pdf to down load...