KUPPLUNGSEINHEIT EINES AUTOMATISCHEN MECHANISCHEN GETRIEBES

A lubrication system for an automatic transmission clutch assembly having a drive and driven rotary member (32, 36) rotatable by a common axis with a clutch element (38, 40) therebetween for connecting and disconnecting the members. The drive member (32) has an internal passageway (62) formed therein for feeding the lubricant to the clutch member. The passageway has a section which is radially spaced from the axis of rotation and has a seat (72) formed therein for cooperating with a rotationally speed sensitive valve (74) oriented in the first passageway. Below a first rotational speed, the lubricant pressure maintains the valve against the seat restricting the flow of lubricant to the clutch element. When the driven member is rotated above the first rotational speed. Centrifugal force biases the valve off the seat, allowing lubricant to be supplied to the clutch element. Preferably, a second lubrication passageway (76) is provided having a seat in an internal valve which selectively supplies a lubricant to the clutch element at a second higher rotational speed. In order to further reduce disengaged clutch drag at idle, a speed sensitive piston retract spring (58) is provided to increase piston travel at low engine speeds while maintaining minimum travel at off idle operation.