What Causes PTO Failure on Truck?

PTO meaning

PTO means auxiliary power output, which is a kind of power output, also called power output. PTO is a device that outputs the power of the engine to equipment other than the vehicle drive system. This device is found in many commercial vehicles, such as cement mixer trucks, dump trucks, etc. The PTO of the truck is the auxiliary power take-off. After starting the truck, the PTO sets a certain target speed. Under the control system, the engine will stabilize at this speed, so that the vehicle speed can be maintained at a certain speed, and the vehicle speed will not be changed even if the accelerator is stepped on. It can increase the flexibility of the vehicle and meet the requirements of different vehicles for the PTO function.

The principle of controlling diesel engine PTO: the engine electronic control unit ECU collects the signal of PTO switches and PTO potentiometer, and the ECU analyzes the control strategy to judge whether the current vehicle and engine state meet the PTO control conditions. If yes, the engine enters the PTO mode, and the ECU controls the engine speed to adjust the PID speed according to the calibrated PTO potentiometer voltage-target speed relationship.

What causes PTO failure on truck?

1. The fracture of the power output shaft is one of the common faults on tractors. Now, most of the tractor power output is a two-half type with an external flange, which is convenient for maintenance. It is common that the rear half shaft of the power output with flange is broken. There are also cases where the front half shaft of the power output is broken. If the power output shaft is broken, the universal joint will not turn.
2. The power output transmission shaft is installed in the gearbox and the rear axle. It is rare for the power output transmission shaft to break and the connecting sleeve between the power output transmission shafts to fall off. It happens occasionally. I have encountered it several times in actual maintenance. Once it happens, the universal joint will not turn.
3. If the power output is out of gear and the gear is not in place, it will cause the power output and the universal joint to not rotate. In real situations, the power output is out of gear from time to time, mostly due to gear wear, large gaps, and small self-locking spring pressure. When the load is too high, it will be out of gear.
4. Slipping and burning of the auxiliary clutch. It is also a common fault on tractors. Because the auxiliary clutch is not adjusted properly or the load is too large, the auxiliary clutch will slip and burn when the light-duty telescopic Cardan shaft is in use. At this time, the universal joint will not rotate up too.