What oil should be added to the wheel loader machine gearbox?
There are many kinds of gearboxes for loaders, and the oil they add is different. The gearbox of Shanggong loader needs hydraulic oil, the ZF gearbox needs engine oil, and other planetary gearboxes need hydraulic transmission oil.

Is the loader's gearbox a fluid coupling?
The gearbox is divided into planetary type and fixed-axis type, both of which change the output speed and torque through different gear ratios to achieve the effect of changing the output speed and output torque.

The pump impeller of the loader torque converter is rigidly connected to the engine flywheel, that is, the input speed of the torque converter and the output speed of the engine are always consistent. The loader's torque converter will have a variable speed pump. This

The main function of the pump is to suck oil from the oil pan of the gearbox, supply the transmission oil in the torque converter, and lubricate and cool the various gears and clutch plates in the gearbox.

For a torque converter, the main parameters are the transmission ratio and the torque ratio. For torque converter manufacturers, they generally provide a thousand-rpm torque to match the engine and the torque converter.

The working principle of the torque converter is that the torque converter pump wheel directly connected to the engine rotates, stirring the transmission oil in the torque converter and moving according to certain rules. There is a fixed guide wheel in the middle of the hydraulic torque converter. When the liquid passes through When the stator wheel goes through various complex changes, it impacts the output turbine and drives the turbine to rotate to achieve the effect of increasing torque. When the torque is increased, the output speed of the turbine will decrease.

Repair and maintenance of damaged front wheel loader transmission shifting mechanism
1. Causes of clutch damage: When the power shift transmission clutch is engaged, the pressure of the hydraulic oil overcomes the spring force and compresses the friction plate. As the hydraulic oil pressure increases, the friction plate contacts the metal plate and gradually tightens, allowing the clutch to smoothly transmit the flywheel power to the transmission input shaft. Every time you shift gears, the friction plate rubs against the steel plate, and the heat generated is dissipated by the coolant. When the friction plate and steel plate become thinner, more hydraulic oil is required to fully engage them, the engine must be further accelerated, and the sliding time of the friction plate on the steel plate is also extended, and the resulting friction heat will also be greater. This causes the temperature of the hydraulic oil to increase. When it reaches a temperature high enough to change the performance of the seals in the transmission, internal leakage will occur in the transmission. Internal leakage continues to cause an increase in heat from two aspects: high-pressure oil leaks through the damaged seal, causing the oil temperature to continue to rise; due to oil leakage, the hydraulic pump is bound to deliver more oil to ensure that the clutch is engaged. The required pressure is required to fully engage the clutch, which also requires the engine to continue to accelerate, causing the hydraulic pump to generate greater flow. Such a vicious cycle will eventually lead to the clutch overheating or burning, until it completely fails.

2. Detection of clutch piston sealing. When the loader is unable to move or the oil temperature is too high, it is necessary to determine whether the clutch piston seal is not tight or the oil pressure is insufficient. However, conventional detection methods are sometimes difficult to determine which cause the failure, especially When there is no power, it is more difficult to check the sealing rings of the assembled transmission assembly. At this time, the air pressure valve can be used for testing. First, remove the transmission control valve (for an assembled transmission, before installing the control valve), and then pass 0.6 to 0.8MPa gas into each oil hole of the transmission in turn. If a certain hole is filled with gas, you hear " If there is a "bang" sound and there is no air leakage sound or the air leakage sound is very small, it means that the seal between the corresponding clutch piston and the cylinder barrel is good; if there is no sound of the piston pressing the friction plate and there is no air leakage sound, If it is larger, it means that the seal between the clutch piston and the cylinder tube has failed, and the seal should be replaced.

3. Prevention of loader transmission failure The bearings and gear pairs of the power shift transmission are vulnerable parts, so the loader transmission should be inspected and maintained regularly. The typical maintenance interval of foreign transmissions is 5,000 to 10,000 hours. According to my country's national conditions, it is recommended that the clutch wear should be checked every 2500 to 5000 hours, and abnormal signals should be caught at any time. Since the power shift transmission is unlikely to fail quickly, it can usually continue to be used for 750-1000 hours after the friction plates first show signs of wear. If regular inspection and maintenance are performed during this period, and friction plates, seals and individual bearings are replaced in time, damage to undamaged parts (such as steel plates, gears, shafts, hydraulic cylinders and most bearings, etc.) can be avoided.

4. The following abnormal conditions often occur before the clutch fails:
(l) Although the machine can still work, the oil in the transmission has deteriorated, its viscosity has dropped and it contains metallic impurities. Therefore, transmission oil samples should be analyzed more frequently before the recommended oil change interval. Because clutch wear is a sign of transmission failure, if metal impurities enter the gear pair or jam the gears so that they cannot be aligned, other components in the transmission will be crushed if the engine is not shut down.
(2) Decreased shifting performance is a sign of clutch damage. When the clutch begins to slip, the machine will rush forward even if it is accelerated smoothly. At this time, the machine should be shut down for maintenance.
(3) The clutch control oil level drops, and when the machine must accelerate to engage the clutch, it means that the clutch has been excessively worn or has a seal failure. Therefore, clutch wear can be determined by measuring the oil pressure of the loader transmission and observing whether the oil temperature rises. At the same time, the oil quality should also be analyzed. If iron or chromium particles appear in the oil, it indicates that the gear pair has begun to wear. To sum up, if the seals and friction plates are replaced before the clutch fails, the maintenance cost will be 30% lower than repairing after the clutch fails. Similarly, if the planetary gearbox or gear pair is repaired before it fails, the cost will be 2/3 lower than repairing a completely damaged transmission.