One. Consideration from the engine: the selected gearbox to match the engine torque, there is now a common misunderstanding, many people in the case of the engine does not change, that the greater the torque of the gearbox the better, in fact, this not only increases the cost of additional configurations, but also because of the increase in fuel consumption and increase the operating costs, the benefits do not outweigh the losses.
The selected gearbox should be consistent with the corresponding installation dimensions of the engine. There are four issues: the diameter of the first shaft of the gearbox should be consistent with the inner diameter of the clutch disc; the clutch specification should be consistent with the clutch housing on the gearbox; there are two types of holes in the clutch housing of the engine: Φ12~10.8mm and Φ12~12.5mm, which should be noted when purchasing a gearbox; for the same level of engine, the front bearing position of the first shaft of the gearbox designed by different manufacturers may be different, so the first shaft of the gearbox should have a different design, so the first shaft of the gearbox should have a different design. For the same level of engine, different manufacturers may design the front bearing position of the first shaft of the gearbox on the clutch differently, so the length of the first shaft (i.e., shaft extension) of the gearbox is also different accordingly.
Two. Consideration from the use of the vehicle: whether the car is loaded with dump trucks or flatbed trucks, whether it is more in the mountainous areas or more in the plains, for dump trucks or more in the mountainous areas, it is best to use the gearbox without overdrive and a gear speed is relatively large (is the speed ratio is large, rather than the driving speed is large), so that for the service life of the engine and the gearbox are good; but if it is loaded with flatbed trucks, it is best to use the gearbox with overdrive and a gear speed is relatively large; however, if it is loaded with flatbed trucks, it is best to use the gearbox with overdrive and a gear speed is relatively large. But if you are loading a flatbed truck, it is better to choose a gearbox with an overdrive gear and a smaller first gear, so that it can run fast with high economic efficiency.
Three. Consideration from the driving structure: the cab has a flat head and pointed points, gearboxes with which it is also compatible with the remote (i.e., through the flexible shaft connection) operation and direct operation. For long-distance operation of the transmission, but also divided into the operation axis left and right (i.e., from the back to the front, the top cover of the operation axis is in the left or right), to the same kind of placement, and there are gear selector arm near the connection and far from the connection of the points in the purchase of gearboxes have to be clear.
Four. Consider from the braking method: now the braking method is generally divided into two kinds of handbrake and air brake, now there is a big trend to replace the handbrake with air brake.
Five. Consider from the type of drive shaft: In order to connect smoothly with the drive shaft, the output flange of the gearbox is divided into 153 flange, 145 flange, 140 flange, isometric four-hole flange, isometric eight-hole flange (i.e., Hanging Gear Flange) and so on.
Six. Consideration from the rear axle speed ratio: rear axle speed ratio is different, with the matching gearbox odometer speed ratio is also different, otherwise, the speedometer, odometer reflects the speed and mileage is not real. Batch loading, must be launched according to the rated speed, rear wheel diameter, rear axle speed ratio accurately calculate the speed ratio of the odometer gears, the selection of the corresponding transmission, maintenance and replacement must be selected from the original model of the transmission.