Transmission shifting assembly and method

A transmission servo assembly configured to be disposed in an assembly housing including an aperture at a first end, the transmission servo assembly comprising:

• a servo pin movable between a resting position and a biased position, said servo pin having an exterior surface coaxial with a longitudinal axis and being configured to extend through said aperture at the housing first end, said servo pin including a fluid pathway and a plurality of apertures extending from said fluid pathway to said exterior surface of said servo pin;
• a primary piston coaxial with said servo pin and having an interior surface that slidingly engages said exterior surface of said servo pin, the primary piston comprising a larger diameter region and a tubular region extending from the larger diameter region along said servo pin opposite the housing first end;
• a secondary piston coaxial with said primary piston and said servo pin abutting said tubular region of the primary piston, wherein said secondary piston has an interior surface that slidingly engages said exterior surface of said servo pin, and wherein said primary piston and said secondary piston coact to move said servo pin relative to said aperture;
• a separator slidingly disposed around said tubular region of the primary piston in sealing engagement therewith;
• a biasing member having a first end in contact with said primary piston and a second end in contact with said assembly housing, and wherein said biasing member is designed and configured to exert a biasing force to said primary piston and said secondary piston;
• a first chamber and a third fluid chamber in fluid communication with said fluid Pathway;
• and
• a second chamber communicating with a fourth chamber, said second chamber and said fourth chamber being fluidly isolated from said first chamber and said third chamber within said assembly housing, wherein said second and fourth fluid chambers provide apply pressure to said primary and secondary pistons, respectively.