Some models with K7M and F3R engines are equipped with a four-speed automatic transmission (refer to accompanying illustration).
The transmission consists of a torque converter, an assembly of epicyclic gears, clutches, brakes and an electronic control unit.
The torque converter ensures that the drive plate is engaged with the transmission, as well as changing gear ratios during acceleration.
Engagement of reverse gear or one of the four forward gears is carried out depending on which of the components of the epicyclic gear assembly is blocked (with brakes and clutches) or rotates. The transmission pump provides the necessary hydraulic pressure to operate the brakes and clutches.
Pulses from switches and sensors associated with the transmission flap and gear selector rods are analyzed in an electronic device that determines the gear ratio and controls the operation of the transmission. The device activates solenoid valves that alternately open or close hydraulic channels, causing the clutches and brakes to engage or release the respective components of the gear assembly.
The transmission fluid is cooled by the coolant passing through a special radiator mounted on the transmission.
Due to the complexity of the automatic transmission device, its repair and diagnostics should be entrusted to a Renault workshop equipped with the necessary special equipment. The contents of the following Sections are therefore limited to a general description and maintenance procedures for the unit.