9.1. General information
During a start of motion of AT acts as ordinary coupling, and at the movement of the car performs work on gear shifting.
The AT main hubs are: torque converter (hydrotransformer), planetary reducer, hydraulic or electronic control units. Hydrodriving disk and tape brakes and disk couplings are applied to transition to other transfer relation in a planetary reducer.
The torque converter on the functions corresponds to hydraulic coupling. Its task includes implementation of coupling at a start of motion and gear shifting. The hydrotransformer is equipped with the blocking coupling which is carrying out direct coupling of the engine with AT.
The control system of automatic transmission is accompanied by a control system of the engine by means of the tire of CAN and on the basis of the analysis of the data arriving from various information sensors (not necessarily directly related to functioning actually of AT), chooses optimum from the point of view of profitability, smoothness of switchings and other the mode of functioning of AT. AT has the control unit (TCM). At failure detection in memory of the control unit the corresponding code registers (see Specifications to the Head Sistemy of electric equipment of the engine).
The only procedures of service of AT which implementation has to be made on a regular basis is check of level of its working liquid (ATF) and replacement of ATF. The order of implementation of these procedures is stated in the Sections Check of Levels of Liquids, control of leaks and Replacement of the AT gearbox oil (according to) the Head Nastroyki and routine maintenance of the car.
Thanks to application of D/V of the P / N modes (PNP sensor) start of the engine can be carried out only when the lever of the AT selector is in situation "P" or "N" that allows to prevent the casual movement of the car in start attempt.
At an exit of their system of the sensors which are used the TCM, AT block switches over works to emergency operation. At the same time the car can the engine forward only on the 4th transfer. Ø/m valves of gear shifting are cut off power.
Only the general information on work and design of AT is provided in the present Chapter.
The repair of AT connected with its dismantling should be charged to experts.