Lull 644-tt Highlander Issues and Troubleshooting

[MikePhua]

Introduction
The Lull 644-tt Highlander is a versatile telehandler used in various industries for lifting and material handling. However, like any piece of heavy equipment, it may encounter mechanical issues over time. This article discusses common problems and provides troubleshooting advice for the Lull 644-tt Highlander to help users maintain optimal performance.
Common Symptoms of Issues
Users of the Lull 644-tt Highlander have reported several issues with the machine, primarily relating to its lifting capacity, hydraulic performance, and electrical systems. Symptoms such as difficulty in lifting loads, unresponsive controls, and hydraulic fluid leakage are some of the most common complaints.
Potential Causes and Solutions

1. Hydraulic Problems
   • Symptoms: Slow or unresponsive lifting, hydraulic fluid leakage.
     
   • Cause: A common cause for hydraulic issues is a low fluid level, worn-out hydraulic seals, or malfunctioning hydraulic valves.
     
   • Solution: Begin by checking the hydraulic fluid levels and topping them up as needed. Inspect the hydraulic hoses, fittings, and seals for any signs of wear or leakage. If there are no visible leaks, the issue may lie with the hydraulic valve or pump, which might require professional attention.
     
2. Electrical Malfunctions
   • Symptoms: The telehandler fails to start, or the electrical system operates inconsistently.
     
   • Cause: Battery issues, faulty alternators, or damaged wiring can lead to electrical malfunctions.
     
   • Solution: Start by checking the battery voltage and charging system. Ensure that the battery terminals are clean and free of corrosion. If the alternator is not charging the battery, it may need replacement. Inspect all wiring for any loose connections or damaged wires.
     
3. Lift and Boom Problems
   • Symptoms: Difficulty in extending the boom or lifting loads.
     
   • Cause: This may occur due to malfunctioning boom cylinders, a weak hydraulic system, or poor lubrication of moving parts.
     
   • Solution: Check the boom cylinders for any signs of leakage. Ensure that all pivot points are properly lubricated, as dry components can cause additional strain on the system. If the problem persists, further investigation into the hydraulic valves or pump might be needed.
     
4. Transmission Issues
   • Symptoms: Difficulty shifting gears or the telehandler stalling.
     
   • Cause: Low transmission fluid, faulty solenoids, or damaged transmission components can lead to transmission malfunctions.
     
   • Solution: Inspect the transmission fluid levels and refill if necessary. Check the solenoids and transmission lines for any visible leaks or damage. If the transmission fluid is dark or smells burnt, it might be time to replace the fluid or address underlying mechanical issues.
     
5. Brake Problems
   • Symptoms: The machine fails to stop promptly, or there is a lack of braking power.
     
   • Cause: Worn brake pads, air in the brake lines, or low brake fluid.
     
   • Solution: Inspect the brake pads and replace them if they are worn. Check the brake fluid levels and top them up if needed. If air in the brake lines is suspected, a brake system bleed might be necessary to remove air pockets and restore braking efficiency.
     

Preventative Maintenance Tips
To avoid these issues from arising in the first place, regular maintenance is crucial. Users should:

1. Monitor Fluid Levels: Regularly check and maintain hydraulic and transmission fluid levels to ensure proper machine function.
   
2. Clean and Lubricate: Clean the machine and lubricate all moving parts to reduce wear and tear.
   
3. Check Electrical Connections: Keep electrical connections clean and free from corrosion to avoid power failures.
   
4. Inspect for Leaks: Conduct frequent inspections for hydraulic or fuel leaks to address minor issues before they become significant problems.
   

Conclusion
While the Lull 644-tt Highlander is a reliable piece of equipment, it can face mechanical and electrical challenges over time. Regular inspections and addressing issues like hydraulic malfunctions, electrical failures, and transmission problems promptly will help extend the lifespan of the telehandler and ensure it continues to perform effectively. If you are unable to resolve the issue through basic troubleshooting, consulting a professional technician is advised.