Patent ID: 8727942

Claim:
An apparatus for controlling fluid flow in a motor vehicle transmission, comprising: a first pump driven by an input shaft of the transmission to supply fluid from a source of fluid to at least one friction engagement device via a first fluid passageway, a second pump driven by the input shaft of the transmission to normally supply fluid from the source of fluid to a lubrication and cooling sub-system of the transmission via a second fluid passageway, a first valve fluidly coupled between the first and second fluid passageways and directing fluid from the second fluid passageway to the first fluid passageway when fluid pressure in the second fluid passageway is greater than fluid pressure in the first fluid passageway by at least a threshold pressure amount, and a second valve fluidly coupled to the first and second fluid passageways and to the lubrication and cooling sub-system, the second valve blocking the first and second fluid passageways from the lubrication and cooling sub-system when a flow rate of the fluid in the first fluid passageway is less than a first threshold fluid flow rate, a temperature of the fluid is greater than a temperature threshold and a fluid flow demand is greater than a fluid flow demand threshold such that fluid pressure in the second fluid passageway exceeds the fluid pressure in the first fluid passageway by at least the threshold pressure amount, whereby fluid is supplied by the first and second pumps only to the at least one friction engagement device via the first fluid passageway.