In block drive systems, in which the gearbox is located close to the main transmission, two-shaft gearboxes are used. The torque is transferred directly from the engine to the intermediate shaft, here also fulfilling the role of a clutch shaft. From the main shaft, the drive goes directly to the main gear, usually located in a common housing with the gearbox.
The gearbox shafts are mounted in roller bearings. However, the presence of oil in the gearbox, necessary for the lubrication of gears and synchronizers, enables the use of plain bearings to seat the gears on the main shaft. As a result, the dimensions of the gearbox are reduced.
Gear shifting requires shifting the gears, toothed clutches or synchronizers. Transfer of power and shifting from the gearshift lever - driven by the driver - to the shift forks, acting directly on the sliding elements, enables the gearbox control mechanism.