Gehl 4510 Tandem Pump Issues

[MikePhua]

Machine Background and Brand History
The Gehl 4510 skid-steer loader is equipped with a Ford gasoline engine and delivers approximately 40 horsepower, with an operating weight around 4,230 lb and a rated lift capacity near 1,150 lb . Gehl’s rich heritage dates back to 1859, originating in a West Bend, Wisconsin blacksmith shop, evolving through over 150 years into a leader in compact and agricultural equipment . Since the early 1970s, Gehl has produced skid-steer loaders, expanding its line over decades to encompass a wide range of models and applications .
Typical Tandem Pump Trouble
Operators of the 4510 occasionally face issues with the hydraulic tandem pump assembly—often the Eaton-manufactured unit that is shared across Gehl models such as the 4510, 4610, 3515, and 3615 . A common complaint is leaking oil from the control shaft area of the drive pump. This leak tends to occur even when the machine is shut off, suggesting seal deterioration.
Probable Cause and Repair Insight
The leakage is typically due to a failing lip seal or O-ring around the rotating control shaft. Despite the small shaft diameter (often under half an inch) and the shaft not rotating 360°, such seals are used and must be replaced from the inside—meaning the pump must be partially dismantled to access the seal effectively .
Repair steps generally involve:

• Removing the arm or coupling to expose the pump shaft.
  
• Accessing and replacing the lip seal or O-ring kit.
  
• Reassembling, ensuring proper seating and avoiding over-torquing.
  

It’s noted that service parts should be ordered by serial number because sealing arrangements may vary between assemblies .
Tandem Pump Assembly Availability
Reconditioning or replacing the tandem pump assembly may be an option. A remanufactured Eaton tandem pump assembly (OEM part number 083694) suitable for the 4510 and related models is available, priced around $2,995, with a core charge of approximately $1,500 to be refunded upon return of the old unit .
Terminology Clarified

• Tandem pump assembly: two hydraulic pumps combined (e.g., gear pump + control pump) supplying different circuits.
  
• Lip seal: a seal with a flexible lip that keeps fluid contained around a rotating shaft.
  
• Core charge: a refundable deposit paid when purchasing a remanufactured part, returned upon return of the old core.
  
• Serial-number–specific seal kit: replacement parts matched to the exact equipment variant for compatibility.
  

Small Story from the Field
A fleet operator noticed oil dripping near the loader’s cylinders after shutdown. Investigation revealed seepage at the drive pump area. After solving traffic scheduling, the mechanic removed the front loader arm to gain access. Inside, a deteriorated lip seal was replaced using a service kit. The loader returned to service the same day, leak free. The lesson: a small seal can be at the root of persistent oil loss, and replacement may spare much greater downtime.
Recommendations for Owners and Technicians

• Inspect around the drive pump area for persistent oil traces, especially along the control shaft or linkage.
  
• When faced with leaks, plan for partial pump disassembly—don’t attempt to fix externally.
  
• Order seal kits using the machine’s serial number to ensure correct fit and avoid mixing configurations.
  
• Assess cost-benefit of repairing versus reman buying. For machines with advanced wear, a remanufactured pump assembly may offer reliability with a modest time savings.
  
• After seal replacement, monitor under load and idle for recurrence over the next 20-50 hours.
  

Summary List

• Model: Gehl 4510 skid-steer loader; ~40 hp Ford gas engine; ~4,230 lb weight; ~1,150 lb capacity .
  
• Brand history: Founded 1859, 150+ years heritage, skid-steer production since early 1970s .
  
• Common issue: Leak from control shaft of tandem hydraulic pump.
  
• Cause: Worn lip seal or O-ring—requires internal access .
  
• Replacement: Kit available; order by serial number .
  
• Reman pump: Eaton tandem pump assembly ~ $2,995 with core value ~ $1,500 .
  
• Tips: Inspect, plan disassembly, order correct parts, consider full reman unit.