Engageable coupling assembly having reduced spin losses and method of assembling such assembly within an automotive transmission to reduce such losses

A method of assembling a clutch assembly into an automotive transmission to reduce spin losses, the method comprising:

• providing an engageable clutch assembly adapted for use with pressurized fluid, the assembly including first and second clutch members that are supported with respect to each other for relative rotation about a common rotational axis, wherein one of the clutch members has an annular groove, the clutch members having a first pair of annular faces that oppose each other and define an annular space therebetween, a first face of the first pair having a set of pockets spaced about the rotational axis, a second face of the first pair having a set of locking formations, the clutch members having a second pair of annular faces that oppose each other and define a set of fluid passages fluidly communicating the annular space with an exterior surface of the assembly;
• the assembly further including an annular retaining member that is received by the annular groove to retain the clutch members together wherein a rotating one of the clutch members has the exterior surface, the exterior surface defining a plurality of pumping grooves in fluid communication with the set of fluid passages and wherein the pumping grooves are configured to pump the pressurized fluid from the annular space, through the fluid passages and over the retaining member during an overrun condition, the retaining member having circumferentially spaced opposite ends which define a gap;
• and
• assembling the clutch assembly into the transmission so that the gap is at the bottom of the assembly wherein fluid within the assembly is allowed to drain from the annular space, through the fluid passages and the pumping grooves and through the gap when the rotating one of the clutch members is not rotating to reduce spin losses when overrunning occurs.