PISTON 8P4735 - Caterpillar

Illustration 1 g03772913
(C) Outlet to torque converter
(P) Pressure from pump
(T) Outlet to TankThe relief valve for the transmission control is an Electronic Main Relief Valve (EMRV).This EMRV controls the maximum pressure in the transmission hydraulic system. The EMRV has no mechanical adjustment. The transmission ECM sends a signal to the EMRV when a gear selection is made. Different gear selections may have different relief settings.The EMRV controls the maximum pressure when a gear selection is made. Each individual clutch solenoid controls the pressure to that clutch. A gear selection may engage more than one clutch, and each clutch may have a different pressure.Transmission pump oil comes from passage (P) to relief valve. When the pressure of the oil reaches the relief pressure, the relief valve allows oil to flow through passage (C) to the torque converter.