- Check the oil levels.
Inspect the oil levels in both sections of the hydraulic tank.
Note: Many problems in the power train are caused by low oil levels or by air in the oil. If the engine has not been started for several minutes, this oil level check will ensure that oil is in the transmission and that the engine can be started. If the machine has not been moved overnight or an extended period of time and the engine has not been started, the oil level will be high. An accurate oil level check can be performed after the oil is hot.
- Check for leaks.
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Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks. |
Inspect all oil lines, hoses, and connections for damage or for leaks. Look for oil on the ground under the machine.
Note: If oil can leak out of a fitting or a connection, air can leak into the system. Air in the system can be as bad as a low amount of oil.
- Check the electrical system.
Inspect the circuit breaker for the Power Train Electronic Control Module, the harnesses, and the electrical connectors. Refer to the proper Electrical Schematic.
With the engine start switch and the battery disconnect switch in the OFF position, check the circuit breaker for the Power Train Electronic Control Module. If the circuit breaker is open, reset the circuit breaker.
Inspect the electrical harnesses for damaged wires or for broken wires. Disconnect each connector and look for pins and sockets that have been bent, broken, or removed. Look for any foreign material inside the connectors. The connectors must be tightened with normal force. The connectors must be disconnected with the same amount of force.
For additional instructions, refer to Service Manual, "773F, 775F, and 777F Power Train ECM".
- Check the batteries.
Check the batteries. Turn the battery disconnect switch ON.
- Check the filters and the screens.
Inspect the torque converter oil filter, the transmission oil filter, the transmission magnetic screen, and the suction screens.
Note: The torque converter oil filter and the transmission oil filters have bypass valves. A bypass valve allows oil to bypass the oil filter elements whenever the difference in pressure between the inlet oil and the outlet oil in the oil filter is too high. Any oil that does not go through the filter elements goes directly in the hydraulic circuit. Dirty oil causes restrictions in the valve orifices, the sticking valves, etc.
If any contamination is found in the elements of the torque converter oil filter or in the screens, all the components of the torque converter, hoist, and brake hydraulic system must be cleaned. Do not use any damaged parts. Any damaged parts must be removed and new parts must be installed.
If any contamination is found in the elements of the transmission oil filter or in the screens, all the components of the transmission hydraulic system must be cleaned. Do not use any damaged parts. Any damaged parts must be removed and new parts must be installed.