FEATURES OF DESIGN AND DIAGNOSTICS OF AUTOMATIC TRANSMISSIONS OF THE GM 6T FAMILY

Automatic transmission (AT) is a complex hydroelectromechanical system, since it consists of hydraulic, electrical and mechanical parts. Automatic transmission of the 6T family is mainly used on cars manufactured by "UzAuto Motors", 6-speed AT family GM 6T30, 6T40, 6T45, 6T50 "Hydra-Matic". The differences between AT 6T30/6T40/6T45/6T50 are in the thickness of the output chain and in the planetary gear, in the sizes of some other units and the housing itself. But the differences are much more strongly influenced by the transmission unit settings, which select operating modes with different engines so as not to overload the most delicate parts of the automatic transmission. 6T30, 6T40, 6T45, 6T50 have the ability to manually shift gears and activate the "kickdown" mode (for quick acceleration of the car, when you sharply press the gas "all the way" it forces the automatic to lower the gear, and sometimes by two). The operation of the transmission is controlled by various electronic systems that are responsible for the operability and structural integrity of the gearbox. Failure of the automatic transmission can occur as a result of one or a combination of faults in the following parts: in the torque converter; in the mechanical part of the gearbox; in the hydraulic part of the control system; one or more clutches of the gearbox; in the electrical part of the control system; in the electronic control unit. The occurrence of faults and failures depending on the temperature of the working fluid of the automatic transmission of a passenger car was determined. Also, the dependence of the automatic transmission resource on the temperature of the hydraulic fluid was obtained. Qualified diagnostics of the automatic transmission and its control system can in many cases eliminate expensive repairs. - without thorough diagnostics, it is impossible to subject the automatic transmission to routine or major repairs. Only on the basis of diagnostic information can a conclusion be made about the technical maintenance or repair of the automatic transmission. - based on real experience of operating passenger cars equipped with an automatic transmission, we recommend changing its oil every 60,000 km under operating conditions in Tashkent. We also recommend conducting diagnostics of the automatic transmission every 20,000 km of vehicle mileage