Переведите . manual and automatic transmissions the transmission is a mechanism that changes speed and power ratios between the engine and the driving wheels. three general types of transmission are in current use: conventional or sliding-gear, hydra-matic, and torque-converter systems. the conventional transmission provides for three or four forward speeds and one reverse speed. it consists of two shafts, each with gears of varying diameters. one shaft drives the other at a preselected speed by meshing the appropriate set of gears. for reverse speed, an extra gear, known as the idler gear, is required to turn the driven shaft in the opposite direction from normal rotation. in high gear, the two shafts usually turn at the same speed. in low, second, and reverse gears, the driven shaft turns more slowly than the driving shaft. when a pair of gears permits the driven shaft to turn more rapidly than the driving shaft, the transmission is said to have overdrive. overdrive is designed to increase the speed of an automobile without taxing the engine beyond what is considered its normal operating limit. the hydra-matic type of transmission combines the automatic clutch provided by fluid coupling with a semiautomatic transmission. a mechanical governor, controlled by the pressure exerted on the accelerator pedal, regulates gear selection through a system of hydraulically controlled shift valves. hydra-matic transmission provides for several forward gears. the torque-converter type of transmission provides an unlimited number of gear ratios with no shifting of gears. the torque converter is a hydraulic mechanism using engine power to drive a pump, which impels streams of oil against the blades of a turbine. the turbine is connected to the drive shaft and causes it to rotate. both hydra-matic and torque-converter systems are controlled by a selector lever on the steering column, which provides also for reverse and sometimes for emergency-low gears.