Patent ID: 7694794

Claim:
A PTO clutch, comprising: an annular PTO clutch assembly including a central opening, a plurality of friction disks and separator plates, and an annular piston moveable to engage or disengage the disks and plates; a clutch shaft inside the central opening and having an internal bore with a lubrication oil inlet end and an activation oil inlet end; a lubrication shut-off valve between the lubrication oil inlet end and the activation oil inlet end, the lubrication shut-off valve slidable between a first position blocking a port between the lubrication oil inlet end and the disks and plates, and a second position opening the port between the lubrication oil inlet end and the disks and plates; and a relief valve in the lubrication shut off valve, the relief valve opening in response to pressure spikes of activation oil and allow activation oil to move from the activation oil inlet end to the disks and plates.