Torque Converter

The 4R44E/4R55E uses a four-element torque converter. The converter contains the standard internal components (turbine, impeller, and stator) for transfer of power and multiplication of torque. It also utilizes a disc-type Torque Converter Clutch (TCC) for maximum fuel economy.

When applied, the TCC provides a mechanical link between the converter turbine and the engine, allowing for a direct mechanical power transfer from the engine to the transmission. The converter clutch pressure plate is applied and released by fluid pressure, which is controlled by the Powertrain Control Module (PCM). The PCM controls the torque converter clutch using a pulse-width modulated TCC solenoid.

Filter

All fluid drain from the fan passes through the filter. The filter and its accompanying seals are part of the fluid path to the fluid pump.

The filter also has a bypass section. This allows the fluid, which is vented at the main regulator valve, to be recirculated to the pump without passing through the filtering element.

Pump

The pump provides the volume of fluid required to charge the torque converter, main control assembly, transmission cooling system, lubrication system and apply devices.

The 4R44E/4R55E has a positive displacement gear and crescent-type pump which is driven by the torque converter hub.

Main Control Assembly

The main control assembly and related components are part of the pressure side of the 4R44E/4RSSE hydraulic system. The main control assembly consists of the solenoids, the valve body assembly and the separator plate.

All valves inside the main control assembly are anodized aluminum. This means they cannot be sanded, filed or dressed in any way that may damage the valves' surface. If the valves have any scratches, burrs or nicks that prevent free movement, the main control assembly must be replaced.