Seville V8-300 4.9L (1991)
Torque Converter Clutch: Description and Operation
The Viscous Converter Clutch (VCC) system uses a solenoid operated valve in the automatic transmission to couple the engine flexplate to the input
shaft of the transmission through the torque converter. This reduces the slippage losses in the converter, which increases fuel economy. For the converter
clutch to apply, two conditions must be met; internal transmission fluid pressure must be correct, and the PCM/ECM must ground the VCC solenoid in
the transmission.
A normally closed brake switch is used in series with the clutch apply solenoid and the PCM/ECM supplies the ground for the solenoid. When the VCC
brake switch is opened, the clutch will release and this will also signal the PCM/ECM that the brakes have been applied. The VCC system has different
operating characteristics than an automatic transmission without VCC or Torque Converter Clutch (TCC). If the driver complains of a chuggle or surge
condition, the vehicle should be road tested and compared to a similar car to determine if a problem exists. The owner`s manual section on VCC
operation should be reviewed with the driver.
