RT65S Transmission Problems and Solutions

[MikePhua]

The RT65S, a popular model from Terex and now part of the Volvo group, is a compact tracked loader widely used in construction, landscaping, and other heavy-duty applications. Despite its robust design, operators sometimes face transmission issues that can affect the loader’s performance. The transmission, being one of the most critical components in any machine, plays an essential role in transferring engine power to the wheels, allowing the vehicle to move and operate effectively.
When transmission problems occur, it’s crucial to diagnose and address them promptly to avoid costly repairs and downtime. This article covers common RT65S transmission problems, their causes, and suggested solutions based on industry knowledge and operator feedback.
Common RT65S Transmission Issues
The RT65S loader, like all machinery, has its weaknesses when it comes to the transmission system. Operators have reported several issues over the years, which are generally related to the power transfer mechanism, control system, or associated components.

1. Transmission Not Engaging or Slipping
   

One of the most common issues faced by RT65S operators is the transmission not engaging correctly or slipping. In this case, the loader fails to move or shows delayed response to the operator’s input.

• Possible Causes:
  • Low hydraulic fluid levels or dirty hydraulic fluid.
    
  • Worn-out transmission belts or components.
    
  • Faulty hydraulic pump or solenoids.
    
  • Leaking transmission seals.
    
• Suggested Solutions:
  • Check Hydraulic Fluid: Low or contaminated fluid can cause improper operation of the transmission system. Ensure the hydraulic fluid is at the correct level and clean.
    
  • Inspect Transmission Belt and Components: The belts that help power the transmission can wear out over time. Regular inspection and timely replacement are necessary.
    
  • Test Hydraulic Pump and Solenoids: Malfunctioning hydraulic components can affect transmission response. Replace damaged parts.
    
  • Fix Transmission Leaks: Leaks can cause a drop in pressure, affecting the overall performance. Inspect seals and connections for signs of leaks and replace if necessary.
    

1. Transmission Overheating
   

Transmission overheating can occur if the system is working harder than usual, or if the cooling mechanisms aren’t functioning as expected. This is a serious issue that can lead to permanent damage if not resolved quickly.

• Possible Causes:
  • Dirty transmission cooler or radiator.
    
  • Overloaded machine or harsh operating conditions.
    
  • Faulty fan or cooling system failure.
    
• Suggested Solutions:
  • Clean the Cooling System: Ensure the radiator and cooling components are free from debris or dirt. A clean cooling system will help the fluid maintain an optimal temperature.
    
  • Reduce Load: Overloading the machine can cause the transmission to overheat. Ensure that the load capacity is not exceeded.
    
  • Inspect the Fan and Coolant System: If the fan or cooling system is malfunctioning, it could lead to overheating. Replace the fan or repair the coolant system as needed.
    

1. Erratic or Unresponsive Steering
   

The RT65S uses a hydrostatic transmission system that powers both the steering and movement of the machine. When the steering becomes erratic or unresponsive, it can often be traced back to issues with the transmission system.

• Possible Causes:
  • Low hydraulic fluid or contamination.
    
  • Faulty hydraulic motors or pumps.
    
  • Air in the hydraulic lines.
    
  • Worn steering components.
    
• Suggested Solutions:
  • Check Fluid Levels and Purge Air: Low fluid or air in the hydraulic system can cause erratic steering. Check the fluid and top it off if necessary. Bleed the system to remove any air.
    
  • Inspect Hydraulic Motors and Pumps: Hydraulic components that control the steering may be faulty or worn. Regularly test and replace these components as needed.
    
  • Examine Steering Components: Inspect the steering linkage and hydraulic cylinders for wear or leaks, which can affect steering performance.
    

1. Transmission Warning Light or Error Codes
   

When the transmission system malfunctions, many modern loaders, including the RT65S, are equipped with diagnostic tools that trigger warning lights or error codes. These warnings can indicate that there is an issue with the transmission system, prompting the operator to check the machine.

• Possible Causes:
  • Electronic or sensor failure.
    
  • Faulty transmission control unit (TCU).
    
  • Wiring issues or loose connections.
    
• Suggested Solutions:
  • Scan for Error Codes: Use a diagnostic scanner to retrieve error codes and determine the root cause of the problem. This can point to faulty sensors or a malfunctioning TCU.
    
  • Check the Wiring: Loose or corroded wiring can lead to communication problems with the transmission system. Inspect the wiring and connections thoroughly.
    
  • Replace Faulty Sensors or TCU: If a specific sensor or TCU is identified as the problem, replacing the part will resolve the issue.
    

1. Unusual Noises from the Transmission
   

If the loader makes strange sounds, such as grinding, whining, or clunking, during operation, it may be due to issues with the transmission system. These noises can indicate problems with internal transmission components or insufficient lubrication.

• Possible Causes:
  • Insufficient lubrication.
    
  • Worn-out gears or bearings.
    
  • Debris inside the transmission.
    
• Suggested Solutions:
  • Check Fluid Levels: Ensure that the transmission fluid is at the correct level and is in good condition. Low or dirty fluid can cause excessive wear and unusual noises.
    
  • Inspect Internal Components: If the noises persist, inspect the transmission for worn-out gears or bearings that may need replacing.
    
  • Clean the Transmission: Remove any debris or contaminants inside the transmission housing that could cause damage to the internal components.
    

Preventive Maintenance and Tips
Preventing transmission problems before they arise can save time, money, and effort. Here are some tips for maintaining your RT65S transmission:

1. Regular Fluid Changes: Replace hydraulic and transmission fluids according to the manufacturer’s maintenance schedule to prevent overheating and ensure smooth operation.
   
2. Check for Leaks: Regularly inspect hydraulic lines, transmission seals, and other components for signs of leaks. Address any issues promptly to avoid fluid loss and pressure drops.
   
3. Monitor Load Limits: Avoid overloading the RT65S beyond its capacity to reduce strain on the transmission and prevent overheating.
   
4. Service Filters: Replace hydraulic and fuel filters at regular intervals to prevent contamination and ensure proper fluid flow.
   
5. Follow the Manufacturer’s Manual: Always consult the operator’s manual for specific troubleshooting and maintenance instructions.
   

Conclusion
Transmission issues in the RT65S can be frustrating, but with proper care and maintenance, many common problems can be avoided or fixed. Regular inspections, fluid checks, and prompt attention to warning signs will help ensure the machine remains in good working condition for years. Understanding the causes of transmission problems and addressing them early on can save you from costly repairs and minimize downtime, keeping your RT65S loader working at its best.