SkyTrak Won't Move Unless You Engage a Hydraulic Function: Troubleshooting Common Causes

[MikePhua]

When operating a SkyTrak telehandler or similar machines, encountering issues where the unit won’t move unless a hydraulic function is engaged can be perplexing. This problem is relatively common and can be caused by a range of issues, from simple mechanical failures to more complex hydraulic system problems. Understanding the potential causes, how to diagnose the issue, and steps to resolve it is essential for ensuring your equipment runs smoothly.
Common Causes for SkyTrak Not Moving Without Engaging Hydraulic Function

1. Hydraulic Lock or Low Hydraulic Fluid:
   One of the most frequent causes for a SkyTrak or any telehandler not moving until the hydraulic system is engaged is a hydraulic lock or insufficient hydraulic fluid. The telehandler's hydraulic system is responsible for various critical functions, including the movement of the drive wheels. If the hydraulic fluid level is low or there is a restriction, the fluid cannot flow properly, preventing movement.
   • Solution: Begin by checking the hydraulic fluid levels. If they are low, top them up with the correct type of fluid as specified by the manufacturer. If the levels are fine but the issue persists, inspect the hydraulic lines for any signs of leaks or blockages that could restrict fluid flow. In some cases, a clogged hydraulic filter can also prevent proper fluid circulation, so check and replace the filter if necessary.
     
2. Hydraulic Pump Issues:
   The hydraulic pump on a SkyTrak is responsible for supplying pressure to the hydraulic system. If the pump is malfunctioning or if there is an issue with the pump’s seals or bearings, the system may not function properly, preventing the machine from moving until a hydraulic function is engaged.
   • Solution: Test the hydraulic pump’s output pressure. If it’s below the required threshold, the pump may need to be serviced or replaced. In some cases, air may have entered the hydraulic system, leading to cavitation and a loss of pressure. Bleeding the system may help restore normal operation.
     
3. Transmission or Drive System Problems:
   SkyTrak units rely on a combination of hydraulic and mechanical systems to transfer power to the wheels. A malfunction in the drive system, such as a problem with the transmission or the drive motor, can result in the machine being unable to move unless the hydraulics are engaged. This could be due to worn-out components or damage within the transmission.
   • Solution: Inspect the transmission fluid and ensure it is at the proper level. If there’s any sign of contamination or deterioration in the fluid, it may be necessary to flush and replace it. Additionally, check for any mechanical issues with the drive system, such as slipping gears or worn-out clutches, that could be preventing movement.
     
4. Electronic Control Issues:
   SkyTrak units are equipped with an advanced electronic control system that governs the interaction between the engine, hydraulics, and transmission. If there is a fault in the electronic system, such as a malfunctioning sensor or a failed controller, it can prevent the machine from moving normally until a hydraulic function is activated.
   • Solution: Check for any error codes or diagnostic messages on the machine’s control panel. Use a diagnostic tool to connect to the SkyTrak’s onboard computer system and retrieve any fault codes. If an issue is identified, it may require resetting the system or replacing faulty components. In some cases, a software update may be necessary to correct electronic glitches.
     
5. Bypass Valve Malfunction:
   Many telehandlers, including SkyTrak units, are equipped with a bypass valve that directs hydraulic pressure to specific functions, such as lifting the boom or moving the wheels. If the bypass valve is malfunctioning, it may prevent the system from properly directing power to the wheels, requiring the operator to engage a hydraulic function to allow movement.
   • Solution: Inspect the bypass valve for signs of wear or malfunction. If the valve is stuck or not operating correctly, it may need to be cleaned, repaired, or replaced. Check for any debris or contaminants that could be preventing proper valve operation.
     
6. Drive Motor Issues:
   The drive motors on a SkyTrak telehandler are responsible for converting hydraulic power into mechanical motion to drive the wheels. If a drive motor is faulty, it may not generate enough force to move the machine without additional hydraulic function being engaged.
   • Solution: Test the drive motor for functionality. If it’s not performing as expected, it could indicate issues with the hydraulic pump or a fault in the motor itself. Inspect the motor for leaks, unusual noises, or signs of wear. If necessary, the drive motor may need to be rebuilt or replaced.
     

Steps to Diagnose and Fix the Issue

1. Check Hydraulic Fluid Levels:
   Start with the most straightforward solution—check the hydraulic fluid levels. Low fluid can often lead to issues with hydraulic pressure, so ensuring the system is properly filled is crucial. If you notice a significant drop in fluid levels, inspect the hydraulic lines and components for leaks.
   
2. Examine the Hydraulic Pump and Filters:
   The hydraulic pump is vital to the operation of the system. Ensure it’s working properly by testing its pressure output. If the pump is underperforming, it may need to be replaced. Also, check the hydraulic filters and replace them if they are clogged or damaged.
   
3. Inspect the Transmission and Drive Components:
   If the hydraulic system seems fine, it’s time to move on to the mechanical components of the drive system. Inspect the transmission fluid and look for any issues with gears or clutches. If there are worn-out components, they may need to be repaired or replaced.
   
4. Check Electronic Controls and Diagnostics:
   SkyTrak units feature electronic systems that manage the machine’s functions. If the machine is experiencing issues, checking for error codes is essential. Use a diagnostic tool to scan for fault codes and address any electronic malfunctions.
   
5. Test the Bypass Valve and Drive Motors:
   If the above steps don’t resolve the issue, inspect the bypass valve and the drive motors. A faulty valve or motor can cause the machine to operate erratically, so addressing any issues in these areas should be a priority.
   

Conclusion
A SkyTrak telehandler that won't move unless a hydraulic function is engaged can be caused by a range of issues, from low hydraulic fluid to electronic faults. By systematically checking the hydraulic system, transmission, electronic controls, and mechanical components, you can identify the root cause and restore proper functionality. Regular maintenance and prompt attention to these issues can help prevent such problems from recurring and ensure the machine continues to perform at its best.