9.1. General information

The Management No. 179 of ARUS publishing house is devoted to the detailed description of the principles of functioning and designs of the modern cars of automatic transmissions used on the majority

4-staged the automatic transmission (AT) consists of the hydrotransformer (the rotation converter), planetary assemblies and hydraulically the operated clutch couplings and brake tapes. Control of functioning of transmission is exercised by ECM by means of the electrooperated valves. AT has three modes of the movement: normal (economic), sports and winter.

The normal (economic) mode is intended for usual style of driving when gear shifting happens at rather low turns of the engine corresponding to the mode of the minimum fuel consumption up. Switching in the sports mode is carried out by means of the button located on the lever of the selector and leads to a delay of the raising switchings of transmission that leads to increase in dynamic characteristics of the car, however is followed by some increase in fuel consumption. The control lamp of "SPORT" warns about inclusion of the sports mode (see the Head Governing bodies and methods of operation at the beginning of the Management). For inclusion of the winter mode of functioning it is intended located to switch on the central console, - start-off of the car from the place at activation of this mode happens from the third transfer that significantly increases quality of coupling of protectors with a slippery paving.

The hydrotransformer (the rotation converter) provides torque transmission from the engine to the transmission. Thanks to the fact that transfer of rotation is carried out in the hydraulic way (through transmission liquid - ATF), start-off of the car and gear shifting happen very smoothly. Besides, the hydrotransformer provides dynamic adjustments of size of torque at dispersal.

The AT planetary mechanism provides a possibility of the choice of four lobbies and one back transfers. The transfer relation of a planetary reducer is defined by what of its elements are blocked and what rotate freely. Blocking and an otpuskaniye of elements of planetary assemblies in AT is made by means of clutch couplings and brake tapes activated according to the teams arriving from the module of management. The hydraulic pump placed in a transmission case the pressure of working liquid necessary for activation of couplings and brake tapes.

The driver operates AT by means of the car installed on a floor and the selector lever having seven provisions. Drive provides a possibility of switching of transmission to any of four forward transfers, at the same time the kickdown function provides automatic transition to a low gear when squeezing against the stop to the accelerator pedal (for the purpose of increase in the transfer relation providing to the car the raised dynamic characteristics necessary, for example, at overtaking commission). In situation "1" forward switchings of transmission are completely blocked and the car can move only on the first transfer. The choice of provisions "2" and "3" provides switchings of transmission between the first two/three transfers, providing an opportunity to make braking by the engine in difficult road conditions (for example, at the movement in the mountain area). It is necessary to remember that switching of AT to a low gear can happen only after adequate decrease in turns of the engine. Reverse corresponds to the choice of the reverse gear, situation "N" (Neutral) - neutral and situation "P" - the parking.

Thanks to inclusion in a chain of start of the special sensor switch (the sensor switch of permission of start) start of the engine becomes possible only in provisions "P" and "N" of the lever of the selector, the same sensor switch provides operation of fires of a backing at transfer of the lever to situation "R".

Management of automatic transmission makes the control unit of transmission (TCM). It obtains information from sensors of position of switches, the sensor of temperature of transmission liquid (ATF), the sensor of speed of the car (VSS) and from the MULTEC block of the indication of load of the engine. TCM operates process of gear shifting by means of four em of valves. Advantages of such management consist in low fuel consumption, smoothness of switching and the choice of programs of the movement (economic, sports, winter).

At incorrect entrance signals or faulty Ý/m TCM valves switches to emergency operation of work of AT. At the same time codes of malfunctions which then can be considered register.

In view of complexity of a design of AT, absence on free sale of replaceable internal components, and need of use of the special equipment, authors of the present manual do not recommend to owners of cars to carry out capital repairs of transmission by own forces. In the present Chapter only procedures of diagnostics of the general refusals of transmission, its routine maintenance, adjustments, removals and installations are considered.

Sometimes, in case of serious breakage, it is more reasonable and simpler to replace transmission, than to spend time and funds for restoration of the failed assembly. Regardless of the chosen way of introduction of the refused AT to action, independent performance of its removal and installation will help to cut down substantially expenses (before make sure that transmission really needs recovery repair).