Why the Gehl 5640E Skid Steer May Creep Unexpectedly

[MikePhua]

The Gehl 5640E and Its Mechanical Heritage
The Gehl 5640E skid steer loader was introduced in the early 2000s as part of Gehl’s mid-frame lineup, designed to offer high breakout force, compact maneuverability, and operator comfort. Gehl, founded in 1859 in Wisconsin, had long been a respected name in agricultural and construction equipment. By the time the 5640E hit the market, Gehl had already sold tens of thousands of skid steers globally, with the 5640E becoming one of its most popular models.
With a rated operating capacity of 1,750 pounds and a 68-horsepower Deutz diesel engine, the 5640E was built for versatility. Its hydraulic system delivered up to 22 gallons per minute, and the machine featured joystick pilot controls, a two-speed drive option, and a rugged chassis suited for rental fleets and owner-operators alike.
Understanding Creep in Hydrostatic Drive Systems
Creep refers to unintended movement of the machine when the drive controls are in neutral. In hydrostatic systems like the one used in the 5640E, this typically means the loader slowly rolls forward or backward without input. While it may seem minor, creep can pose safety risks—especially in tight spaces or when loading trailers.
Hydrostatic drive relies on variable displacement pumps and motors. When the control levers are centered, the swash plates inside the pumps should be neutral, producing no flow. If the swash plate is slightly off-center due to wear, misalignment, or control linkage issues, residual flow can cause the machine to move.
Common Causes of Creep in the Gehl 5640E
Several factors can contribute to creeping behavior:

• Control Linkage Misalignment
  The mechanical linkage between the joystick and the pump swash plate may be worn or out of adjustment. Even a few millimeters of offset can cause unintended flow.
  
• Neutral Detent Wear
  The detent mechanism that holds the control lever in neutral may be weak or damaged, allowing drift.
  
• Hydraulic Valve Leakage
  Internal leakage in the drive control valve can bypass fluid even when the system is supposed to be static.
  
• Pump Swash Plate Drift
  Over time, the swash plate may not return to true neutral due to spring fatigue or contamination.
  
• Electrical Solenoid Faults
  In machines with electronic control assist, a faulty solenoid may fail to hold the valve in neutral.
  
• Improper Tire Pressure or Uneven Load
  While not a hydraulic issue, uneven resistance can cause one side to move slightly, especially on inclines.
  

In 2014, a contractor in Arizona reported that their 5640E would slowly roll forward when parked on level ground. After inspecting the control linkage, they found that the left-hand drive lever was slightly bent from repeated forceful operation. Replacing the linkage and recalibrating the neutral position resolved the issue.
Terminology Notes

• Swash Plate: A component inside a variable displacement pump that controls fluid flow direction and volume
  
• Detent: A mechanical feature that holds a lever in a fixed position, such as neutral
  
• Bypass Leakage: Fluid that escapes past internal seals or valves, causing unintended movement
  
• Pilot Control: A low-pressure hydraulic or electrical signal used to actuate main valves
  

Diagnostic and Adjustment Procedures
To correct creep in the Gehl 5640E:

• Park the machine on level ground and chock the wheels
  
• Start the engine and observe movement with controls centered
  
• Inspect control linkage for wear, bends, or loose fasteners
  
• Adjust linkage rods to ensure true neutral alignment
  
• Check detent springs and replace if weak or broken
  
• Test hydraulic pressure at the drive valve to detect internal leakage
  
• Inspect solenoids and wiring for continuity and proper voltage
  
• Recalibrate joystick centering if electronically assisted
  

Gehl service manuals provide detailed procedures for linkage adjustment and valve testing. For machines with extensive wear, replacing the entire control assembly may be more cost-effective than piecemeal repairs.
Preventative Measures and Operator Tips
To prevent creep from developing:

• Avoid slamming control levers into neutral—use smooth transitions
  
• Perform regular inspections of linkage and detent mechanisms
  
• Keep hydraulic fluid clean and within recommended viscosity range
  
• Replace worn bushings and pivot points before they affect alignment
  
• Train operators to report early signs of drift or inconsistent control response
  

For machines operating in dusty or corrosive environments, sealing linkage joints and using anti-seize compounds can extend service life.
Modern Comparisons and System Evolution
Newer Gehl models such as the R190 and V270 feature electronically controlled drive systems with integrated diagnostics. These machines can detect joystick drift and automatically compensate, reducing the risk of creep. However, they also introduce complexity and require software updates and sensor calibration.
The 5640E, while mechanically simpler, remains a favorite among operators who value tactile feedback and field-serviceable components. With proper care, it can deliver thousands of hours of reliable performance.
Conclusion
Creep in the Gehl 5640E skid steer is a manageable issue rooted in the fine balance of hydrostatic control. By understanding the mechanical and hydraulic interplay behind neutral positioning, operators and technicians can diagnose and correct the problem before it compromises safety or productivity. In compact equipment, precision starts with stillness—and when the machine won’t stay still, it’s time to look beneath the levers.