TORQUE CONVERTER OUTLINE [5R55S]
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• The torque converter of the 5R55S transmission is a four-element component. It contains an impeller, a turbine and a reactor, plus TCC (torque converter clutch) for increased fuel economy.
• The impeller and cover assembly drives the impeller blades and fluid pump. It contains hydraulic fluid and provides a mating surface for the TCC damper assembly.
• The turbine is driven by fluid from the impeller and transmits power to the turbine shaft and planetary gearsets.
• The reactor redirects fluid flow returned from the turbine to the impeller so that it rotates in the same direction as the impeller. This action assists in torque multiplication.
• The reactor has a one-way clutch to hold it stationary during torque multiplication (at lower vehicle speeds) and allow it to rotate (at higher vehicle speeds).
• TCC has the following features:
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― A piston with damper assembly that connects to the turbine and transmission input shaft
― A friction paper surface on the piston (or on a ring connected to the piston) that makes contact with the torque converter cover when TCC is applied
― Fluid that flows through the torque converter and pushes the TCC piston away from the torque converter cover during TCC release
― Fluid that flows through the torque converter and pushes the TCC piston into contact with the torque converter cover during TCC apply
• TCC operates in three stages:
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― Full release
― Controlled modulation
― Full apply
• The TCM controls TCC operation, using the TCC control solenoid.
• TCC control solenoid operation provides the modulation of hydraulic pressure to change the position of the control valves. The control valves change the pressure and direction of fluid flow in the torque converter.
• TCC may be applied in 2nd gear, 3rd gear, 4th gear and 5th gear.
