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The Champion 710A and Its Transmission Control System
The Champion 710A motor grader was produced in the early 1990s by Champion Road Machinery, a Canadian manufacturer known for its robust and mechanically straightforward graders. With a Cummins diesel engine and a GEARCO transmission system, the 710A was designed for road maintenance, snow removal, and grading in remote regions. Its transmission relied on solenoid-actuated clutches and a hydraulic control system to manage gear shifts across forward and reverse ranges.
The 710A’s transmission includes multiple clutch packs—typically labeled A, B, C, D, R, L, and H—each responsible for engaging specific gear ranges. These clutches are activated by hydraulic pressure, controlled by solenoids and monitored through pressure ports.
Terminology Notes
A 1991 Champion 710A exhibited gear engagement failure in multiple ranges. The operator noted that forward gears 1 through 8 were selectable, but only gears 5 through 8 responded. Reverse gears 1 through 4 failed to engage. Pressure readings showed 200 psi at the pump, with clutch packs C and D showing no pressure. Packs A, B, R, L, and H were within normal range.
Key observations:
The absence of pressure in clutch packs C and D suggests a hydraulic delivery issue rather than an electrical fault. Possible causes include:
One Canadian operator shared that his 710A refused to reverse over a small pile unless in first gear. After cleaning a corroded electrical connection, voltage rose from 12V to nearly 14V, and transmission response improved. Another technician emphasized that Champion transmissions are sensitive to voltage fluctuations—anything below 13.5V can cause solenoids to misfire or fail to hold.
A grader mechanic in Alberta noted that cartridge valves can stick due to varnish buildup, especially in machines with infrequent fluid changes. He recommended flushing the transmission and replacing all cartridges if multiple clutch packs show pressure loss.
Preventive Measures and Long-Term Solutions
Transmission pressure loss in a Champion 710A often stems from hydraulic delivery issues or low voltage affecting solenoid performance. While the system is mechanically simple, its reliance on clean fluid and stable voltage makes it vulnerable to age-related faults. By testing pressure at each clutch pack, verifying electrical integrity, and maintaining fluid quality, operators can restore full gear functionality and extend the life of this classic grader. In machines like the 710A, every psi counts—and every volt matters.
The Champion 710A motor grader was produced in the early 1990s by Champion Road Machinery, a Canadian manufacturer known for its robust and mechanically straightforward graders. With a Cummins diesel engine and a GEARCO transmission system, the 710A was designed for road maintenance, snow removal, and grading in remote regions. Its transmission relied on solenoid-actuated clutches and a hydraulic control system to manage gear shifts across forward and reverse ranges.
The 710A’s transmission includes multiple clutch packs—typically labeled A, B, C, D, R, L, and H—each responsible for engaging specific gear ranges. These clutches are activated by hydraulic pressure, controlled by solenoids and monitored through pressure ports.
Terminology Notes
- Solenoid Valve: An electrically controlled valve that directs hydraulic fluid to engage clutch packs.
- Clutch Pack: A set of friction discs and plates that engage or disengage power transmission.
- Cartridge Valve: A modular valve inserted into a hydraulic block, often used for directional control.
- Pressure Port: A diagnostic fitting used to measure hydraulic pressure in specific circuits.
A 1991 Champion 710A exhibited gear engagement failure in multiple ranges. The operator noted that forward gears 1 through 8 were selectable, but only gears 5 through 8 responded. Reverse gears 1 through 4 failed to engage. Pressure readings showed 200 psi at the pump, with clutch packs C and D showing no pressure. Packs A, B, R, L, and H were within normal range.
Key observations:
- No error codes were displayed
- Solenoids and cartridges had been replaced
- Electrical system showed no faults
- Transmission pump pressure was nominal
- Clutch C and D had zero pressure
The absence of pressure in clutch packs C and D suggests a hydraulic delivery issue rather than an electrical fault. Possible causes include:
- Blocked or damaged hydraulic lines feeding clutch C and D
- Faulty cartridge valves not directing fluid correctly
- Internal clutch seal failure preventing pressure buildup
- Low voltage to solenoids, despite no visible electrical fault
- Use a hydraulic gauge to test pressure at each clutch port during gear selection
- Confirm voltage at solenoid terminals under load; target is 14.3V for reliable operation
- Inspect cartridge valves for debris or wear; replace if flow is restricted
- Check transmission fluid level and condition; contaminated fluid can affect clutch response
- Verify alternator output and battery health to rule out voltage drop
One Canadian operator shared that his 710A refused to reverse over a small pile unless in first gear. After cleaning a corroded electrical connection, voltage rose from 12V to nearly 14V, and transmission response improved. Another technician emphasized that Champion transmissions are sensitive to voltage fluctuations—anything below 13.5V can cause solenoids to misfire or fail to hold.
A grader mechanic in Alberta noted that cartridge valves can stick due to varnish buildup, especially in machines with infrequent fluid changes. He recommended flushing the transmission and replacing all cartridges if multiple clutch packs show pressure loss.
Preventive Measures and Long-Term Solutions
- Replace transmission fluid every 1,000 hours or annually
- Clean and torque all electrical connections, especially ground straps
- Test solenoid voltage under load, not just at rest
- Keep spare cartridge valves and solenoids in field kits
- Document pressure readings and gear behavior for future diagnostics
Transmission pressure loss in a Champion 710A often stems from hydraulic delivery issues or low voltage affecting solenoid performance. While the system is mechanically simple, its reliance on clean fluid and stable voltage makes it vulnerable to age-related faults. By testing pressure at each clutch pack, verifying electrical integrity, and maintaining fluid quality, operators can restore full gear functionality and extend the life of this classic grader. In machines like the 710A, every psi counts—and every volt matters.
