US Patent 7213682 Hydraulic fluid storage apparatus for a transmission

A hydraulic fluid storage apparatus for a transmission has a main sump and a secondary sump. The secondary sump is connected with the main sump through a restricted flow passage. The fluid within the main sump is subjected to centrifugal forces by rotating components within the transmission, such that at high speeds and high levels in the main sump, the restricted passage is closed by a centrifugal dam thereby resulting in fluid storage within the secondary sump. The fluid storage in the secondary sump returning to the main sump when the speed of the rotating components is reduced.