An integrated driveline (136, 236, 336, 36, 436) slip clutch (154, 254, 354, 454) system for a large square baler (28) for controlling a transfer of power from a tractor (26) to the baler (28). The clutch (254) system includes a slip clutch (154, 254, 354, 454) having a number of clutch plates (388). The slip clutch (154, 254, 354, 454) is moveable between a disengaged relationship in which no power is transferred from a driveline (136, 236, 336, 36, 436) to a gearbox (140, 240, 340, 40, 440), and one or more engaged relationships in which amounts of power are transferred from the driveline (136, 236, 336, 36, 436) to the gearbox (140, 240, 340, 40, 440). Movement of the slip clutch (154, 254, 354, 454) between engagement relationships may be controlled mechanically (by, e.g., centrifugal force) or electronically. For electronic control, a controller receives input data from sensors (504) concerning operation of the baler (28), and controls a valve to introduce or remove hydraulic fluid to or from a clutch cylinder (276, 376, 476) or a double acting cylinder (496) in accordance with a pressure control profile which ramps hydraulic pressure through levels to achieve the engagement relationships.
