The main nodes of the AT are: torque converter (torque converter), planetary gear and hydraulic or electronic control system. To switch to another gear ratio in the planetary gearbox, hydraulic disc brakes and a disc clutch are used.
The design of a typical AT
1 - Transmission oil filling tube; 2 - Shield; 3 - 13-pin connector; 4 - Transmission; 5 - Cardan shaft flange; 6 - Blocking the parking position; 7 - Selector rod; 8 - Exhaust system; 9 - Bracket of the exhaust system; 10 - Crossbar with support; 11 - Ground connection bus
Cross section of automatic transmission
1 - Input shaft; 2 - ECU; 3 - Intermediate shaft; 4 - Parking lock gear; 5 - Output shaft; 6 - Oil pump; 7 - Torque converter; 8 - Reactor shaft; 9 - Locking clutch of the torque converter; B1 - Multi-disc brake assembly B1; B2 - Multi-disc brake assembly B2; B3 - Multi-disc brake assembly B3; F1 - Flywheel F1; F2 - Flywheel F2; H - Rear planetary assembly; K1 - Multi-disc clutch K1; K2 - Multi-disc clutch K2; K3 - Multi-disc clutch K3; M - Central planetary assembly; V - Front planetary assembly
The torque converter has the same function as a hydraulic clutch. Its task is to carry out the clutch when starting off and shifting gears.
transmission control system (known as electronic synchronous shifting system) is an integral part of the modified engine management system, installed only on models with AT.
The layout of the electronic components of the control system
Location of the AT control unit (N15/3). In the engine compartment, on the right side of the partition
The control system can operate in a special safe mode, which it switches to when any malfunction is detected. In this case, the transmission modes are limited, and the car can be delivered under its own power to the repair shop. When the control system enters the safe mode, the control lamp lights up on the dashboard (contact the head Manual).
Analyzing information coming from various sensors (not only sensors directly related to the transmission), the control system selects the optimal one in terms of economy, smoothness, etc. box mode. At a certain throttle position, the control system can lock up the torque converter so that only fourth and fifth gears are engaged. This achieves a significant reduction in fuel consumption.
The only regular maintenance procedure for the box is to check the fluid level (see Section Checking fluid levels, leak control Chapters Current service). It is not necessary to change the transmission fluid regularly.
A transmission fluid cooler is installed next to the radiator of the cooling system.
There is no traditional kickdown switch. The mode is activated directly by the transmission control system after processing information from the throttle position sensor.
There are several modes of operation of the transmission, each of which can be engaged after moving the selector to one of the following positions: «P», «R», «N», «D», «1», «2», «3», «4» (contact the head Manual).
The engine can only be started if the selector is in position «R» or «N». This is to prevent the car from moving when trying to start (if the selector is set to one of the other positions). Analyzing the information coming from the sensors, the control system allows or prohibits the engine start. The locations of the various relays are indicated in Chapter Onboard electrical equipment).