Troubleshooting a 1985 Champion 720A: Transmission Issues and Solutions

[MikePhua]

Heavy machinery, particularly road graders like the Champion 720A, are essential for construction, roadwork, and grading tasks. These machines are built to endure tough conditions, but like all equipment, they are susceptible to mechanical issues over time. One common problem is when the machine won’t engage in forward (F) or reverse ® gear. This issue can disrupt operations, and identifying the root cause is crucial to getting the grader back in action.
Understanding the Champion 720A Transmission System
The 1985 Champion 720A is equipped with a heavy-duty transmission system designed for reliable performance under challenging conditions. It features a hydrostatic transmission that allows for smooth and precise control over the grader’s movement. However, if the transmission fails to engage in either forward or reverse gear, it can be due to several potential causes.
Common Causes of Transmission Issues in the Champion 720A

1. Low Transmission Fluid: The most common reason for a grader failing to engage gears is low or contaminated transmission fluid. Transmission fluid plays a vital role in lubricating the gears, ensuring smooth operation, and providing hydraulic pressure to the transmission components.
   
2. Faulty Hydraulic Pump: The 720A uses a hydraulic pump to engage the transmission. If the hydraulic pump is malfunctioning, it can prevent the transmission from receiving the necessary fluid pressure, resulting in a failure to shift into gear.
   
3. Worn or Damaged Transmission Components: Over time, wear and tear on key transmission components such as the clutch, gears, or shift linkage can cause engagement problems. This is especially true for older machines that have been heavily used.
   
4. Faulty Electrical Connections: In some models, electrical connections or solenoids control the shifting mechanism. A poor electrical connection or a faulty solenoid can prevent the transmission from engaging correctly.
   
5. Clogged Transmission Filters: If the transmission filters are clogged, fluid flow may be restricted, leading to inadequate pressure in the transmission system. This can prevent the transmission from engaging in forward or reverse gear.
   

Step-by-Step Troubleshooting Process
If your Champion 720A is not engaging in forward or reverse, follow this troubleshooting guide to identify and address the issue.
1. Check the Transmission Fluid
The first step in troubleshooting any transmission issue is to check the transmission fluid levels. Low fluid levels can prevent the transmission from working properly.

• Check Fluid Levels: Locate the transmission dipstick, remove it, and wipe it clean. Reinsert the dipstick and check the fluid level. If the fluid is below the recommended level, top it off with the correct transmission fluid as specified in the operator's manual.
  
• Inspect Fluid Condition: Look at the fluid color and consistency. If the fluid is brown or smells burnt, it may be contaminated and need replacement.
  

2. Inspect the Hydraulic System
A malfunctioning hydraulic pump or low hydraulic pressure can prevent the transmission from engaging.

• Check for Leaks: Inspect the hydraulic system for any visible leaks. Leaks in the hydraulic lines, connections, or cylinders can reduce hydraulic pressure, preventing the transmission from shifting.
  
• Test Hydraulic Pump: If you suspect the hydraulic pump is faulty, it may need to be tested by a professional. A worn or damaged pump can fail to provide the necessary pressure to engage the transmission.
  

3. Examine the Transmission Components
If the fluid level is sufficient and the hydraulic system is functioning correctly, the issue could lie within the transmission components.

• Check the Clutch: The clutch is responsible for disengaging the transmission when shifting gears. If the clutch is worn or damaged, it may fail to disengage properly, preventing the machine from going into gear.
  
• Inspect the Gears: Look for any signs of wear or damage to the gears. Worn gears can prevent the transmission from engaging smoothly.
  
• Inspect the Shift Linkage: A misaligned or worn shift linkage can prevent the gear lever from properly engaging the transmission. Ensure the linkage is properly adjusted.
  

4. Check the Electrical System
Some models of the Champion 720A use electrical components such as solenoids or sensors to control transmission engagement. If these components fail, the transmission may not engage properly.

• Inspect Electrical Connections: Look for loose or corroded electrical connections, particularly at the transmission solenoid and associated components.
  
• Test the Solenoid: If you suspect the solenoid is malfunctioning, it can be tested with a multimeter. A faulty solenoid may need to be replaced.
  

5. Replace the Transmission Filter
Clogged or dirty transmission filters can restrict fluid flow, preventing the transmission from receiving enough pressure to engage gears.

• Locate and Replace the Filter: Refer to the operator’s manual to locate the transmission filter. If the filter is clogged, replace it with a new one. Ensure that the filter is installed correctly to avoid further issues.
  

Additional Considerations for Preventative Maintenance
Preventative maintenance is key to prolonging the life of your Champion 720A and avoiding costly repairs.

• Regular Fluid Changes: Make it a habit to check and change the transmission fluid at regular intervals as specified in the operator’s manual. This helps prevent contamination and ensures smooth transmission operation.
  
• Inspect Hydraulics Regularly: Check hydraulic lines for leaks and keep the hydraulic fluid at the proper levels. Replace hydraulic fluid and filters as needed.
  
• Keep the Machine Clean: Regularly clean the machine to prevent dirt and debris from entering the transmission or hydraulic system.
  

Conclusion
The 1985 Champion 720A is a robust machine designed for heavy-duty road grading tasks. When it fails to engage in forward or reverse, it's often a result of simple issues such as low fluid, hydraulic problems, or wear and tear on key components. By following the step-by-step troubleshooting process outlined above, you can quickly identify and address the root cause of the issue.
Regular maintenance, such as fluid checks, hydraulic system inspections, and replacing worn parts, will help keep your Champion 720A running smoothly for years to come. When in doubt, always consult a professional technician to ensure your equipment remains in top condition.