10-18-2025, 05:30 PM
How to Safely Bypass the Hydrostatic Transmission on a Kobelco WLK9 Loader
The Kobelco WLK9 and Its German Origins
The Kobelco WLK9 wheel loader is a 12,000-pound compact machine powered by a Deutz diesel engine and equipped with a two-speed forward/reverse hydrostatic transmission. Though branded as Kobelco, the WLK9 was originally manufactured by O&K (Orenstein & Koppel), a German company with a long history in rail and construction equipment. O&K’s construction division was later acquired by CNH Industrial, which also owns Case and New Holland. This lineage explains the German-language tags found on the machine and the compatibility with certain Case service networks.
The hydrostatic transmission in the WLK9 uses closed-loop hydraulic circuits to drive the wheels. Without engine power, the hydraulic motors lock fluid internally, preventing the tires from turning. This poses a challenge when attempting to move a non-running unit onto a trailer.
Terminology Notes
To move a non-running WLK9 loader, the hydrostatic system must be bypassed without damaging the motors. Disconnecting hydraulic lines is strictly prohibited, as it can introduce air, cause cavitation, and destroy internal components.
Recommended steps:
One technician in Wisconsin shared that he successfully moved a similar loader by removing the rear drive shaft and disengaging the manual brake. He warned that if the brake acts on the transmission rather than the axle, removing the shaft could cause uncontrolled rolling.
Another operator in Texas recalled a case where a loader freewheeled unexpectedly after motor removal, nearly crushing a crew member. He emphasized the importance of blocking the wheels and using a controlled winch system.
A mechanic in Alberta recommended checking for a bypass valve or tow mode lever—some hydrostatic systems include a factory-installed feature for towing, though this is rare on older models like the WLK9.
Preventive Measures and Recommendations
For regions with temperatures dropping to –25°F, starting a Deutz engine without garage access requires preparation:
Bypassing the hydrostatic transmission on a Kobelco WLK9 loader requires mechanical disconnection—not hydraulic tampering. Removing the drive shaft or motor allows wheel rotation, but only if the emergency brake is properly disengaged. Safety is paramount, as improper handling can lead to uncontrolled movement and injury. With careful planning and respect for the machine’s German engineering roots, even a non-running loader can be moved safely and efficiently.
The Kobelco WLK9 and Its German Origins
The Kobelco WLK9 wheel loader is a 12,000-pound compact machine powered by a Deutz diesel engine and equipped with a two-speed forward/reverse hydrostatic transmission. Though branded as Kobelco, the WLK9 was originally manufactured by O&K (Orenstein & Koppel), a German company with a long history in rail and construction equipment. O&K’s construction division was later acquired by CNH Industrial, which also owns Case and New Holland. This lineage explains the German-language tags found on the machine and the compatibility with certain Case service networks.
The hydrostatic transmission in the WLK9 uses closed-loop hydraulic circuits to drive the wheels. Without engine power, the hydraulic motors lock fluid internally, preventing the tires from turning. This poses a challenge when attempting to move a non-running unit onto a trailer.
Terminology Notes
- Hydrostatic Transmission: A drive system using hydraulic fluid to transmit power from the engine to the wheels.
- Closed Loop: A sealed hydraulic circuit where fluid circulates between pump and motor without external flow.
- Emergency Brake: A mechanical or hydraulic system that locks the wheels when engaged.
- Drive Shaft Removal: Disconnecting the shaft between motor and axle to allow free wheel rotation.
To move a non-running WLK9 loader, the hydrostatic system must be bypassed without damaging the motors. Disconnecting hydraulic lines is strictly prohibited, as it can introduce air, cause cavitation, and destroy internal components.
Recommended steps:
- Inspect the emergency brake system. If manual, ensure it is disengaged.
- Locate the drive shaft connecting the hydraulic motor to the axle.
- Remove the drive shaft from the motor end. This allows the axle to rotate freely.
- Confirm that the motor is bolted directly to the axle. If so, removing the motor itself may also release the wheels.
- Use wheel chocks and secure the machine before attempting movement.
- Winch or push the loader onto the trailer slowly, avoiding sudden shifts.
One technician in Wisconsin shared that he successfully moved a similar loader by removing the rear drive shaft and disengaging the manual brake. He warned that if the brake acts on the transmission rather than the axle, removing the shaft could cause uncontrolled rolling.
Another operator in Texas recalled a case where a loader freewheeled unexpectedly after motor removal, nearly crushing a crew member. He emphasized the importance of blocking the wheels and using a controlled winch system.
A mechanic in Alberta recommended checking for a bypass valve or tow mode lever—some hydrostatic systems include a factory-installed feature for towing, though this is rare on older models like the WLK9.
Preventive Measures and Recommendations
- Never Disconnect Hydraulic Lines: This can cause catastrophic motor failure.
- Use Proper Lifting and Winching Equipment: Avoid relying on manual force.
- Inspect Brake Linkages: Ensure full disengagement before movement.
- Label and Document Shaft Removal: Aids in reassembly and future service.
- Consult Case or CNH Dealers: They may have legacy support for O&K machines.
For regions with temperatures dropping to –25°F, starting a Deutz engine without garage access requires preparation:
- Use a block heater or magnetic oil pan heater overnight
- Install a battery warmer to maintain cranking power
- Switch to winter-grade diesel and anti-gel additives
- Keep a portable jump starter or booster pack on hand
- Consider a diesel-fired preheater for coolant and oil circuits
Bypassing the hydrostatic transmission on a Kobelco WLK9 loader requires mechanical disconnection—not hydraulic tampering. Removing the drive shaft or motor allows wheel rotation, but only if the emergency brake is properly disengaged. Safety is paramount, as improper handling can lead to uncontrolled movement and injury. With careful planning and respect for the machine’s German engineering roots, even a non-running loader can be moved safely and efficiently.
