A filter (10) for filtering debris out of the fluid in a transmission sump (S) prior to the fluid entering a transmission pump (P) is disclosed. The filter (10) includes a filter housing (12) presenting a filter inlet (30), a bypass inlet (32), and an outlet (46). Filter media (14) is disposed in the housing (12) such that fluid flowing from the filter inlet (30) to the outlet (46) passes through the media (14) and fluid flows from the bypass inlet (32) to the outlet (46) without passing through the media (14). A bypass valve assembly (16), shiftable into and out of a closed position, prevents fluid flow through the bypass inlet (32) when the valve (16) is closed.