Removing the Transmission-Mounted Hydraulic Pump on a John Deere 310A Backhoe

[MikePhua]

The 310A and Its Integrated Hydraulic Design
The John Deere 310A backhoe-loader, introduced in the late 1970s, was part of Deere’s early push into integrated construction equipment. It featured a rugged mechanical transmission and a hydraulic system powered by a gear-type pump mounted directly to the transmission housing. This design simplified plumbing and reduced space requirements but made pump removal more complex than on frame-mounted systems.
The pump itself drives off the transmission input shaft, meaning it’s tucked tightly between the torque converter and the bell housing. When the pump fails—whether due to wear, cavitation, or seal leakage—removal requires partial disassembly of the driveline.
Symptoms of Hydraulic Pump Failure
Operators typically notice:

• Slow or weak hydraulic response
  
• Loss of loader or backhoe function
  
• Whining or grinding noises from the transmission area
  
• Hydraulic fluid contamination with metal shavings
  
• Difficulty steering (if hydraulics power steering circuit)
  

In some cases, the pump may seize entirely, stalling the engine or preventing gear engagement.
Preparation Before Removal
Before attempting removal:

• Drain hydraulic fluid and transmission oil to prevent spills
  
• Disconnect battery and secure the machine on level ground
  
• Remove loader frame crossmembers or braces that obstruct access
  
• Label and disconnect hydraulic lines from the pump body
  
• Inspect the pump mounting flange for corrosion or damage
  

If the machine has a front-mounted hydraulic reservoir, ensure it’s fully drained and capped to avoid backflow.
Step-by-Step Removal Strategy
Removing the transmission-mounted pump involves:

• Unbolting the pump from the transmission housing (typically 4–6 bolts)
  
• Carefully sliding the pump rearward to disengage the drive gear
  
• Supporting the pump with a sling or jack to avoid damaging the shaft
  
• Inspecting the drive gear and splines for wear or galling
  
• Cleaning the mounting surface and checking for gasket residue
  

In some cases, the pump may be stuck due to corrosion or seal adhesion. Gentle prying with a flat bar and penetrating oil can help, but avoid excessive force that could crack the housing.
Common Challenges and Workarounds

• Limited clearance: Some operators remove the loader frame or tilt the cab for better access
  
• Seized pump: If the pump won’t budge, heat may be applied to the flange area to break the bond
  
• Shaft alignment: During reinstallation, ensure the pump shaft engages smoothly with the transmission gear—forcing it can damage splines
  
• Gasket sourcing: OEM gaskets may be hard to find; some rebuilders fabricate replacements from high-temp hydraulic gasket material
  

One technician shared that he had to remove the starter and part of the bell housing to gain enough clearance. Another used a custom puller fabricated from threaded rod and a steel plate to extract the pump evenly.
Replacement and Rebuild Options
If the pump is damaged:

• Rebuild kits may include seals, bearings, and gaskets
  
• Aftermarket pumps are available but must match flow rate and pressure specs
  
• OEM pumps from John Deere may be costly but ensure compatibility
  
• Used pumps from salvage machines should be pressure-tested before installation
  

Typical specs for the 310A hydraulic pump:

• Flow rate: ~25 GPM
  
• Operating pressure: 2,000–2,500 psi
  
• Gear type with splined shaft
  
• Transmission-mounted flange with internal drive gear
  

Preventive Measures and Maintenance Tips
To extend pump life:

• Change hydraulic fluid every 500 hours or annually
  
• Use fluid with proper anti-foaming and wear additives
  
• Inspect suction screens and filters regularly
  
• Avoid running the machine with low fluid levels
  
• Monitor for leaks around the pump flange and shaft seal
  

If the machine operates in dusty or abrasive environments, consider installing an external filter or magnetic drain plug to catch early signs of wear.
Conclusion
Removing the hydraulic pump from a John Deere 310A backhoe is a technical but manageable task with the right preparation and tools. Understanding the pump’s location, drive mechanism, and mounting challenges is key to a successful repair. Whether rebuilding or replacing, attention to alignment, sealing, and fluid cleanliness will ensure the machine returns to full hydraulic strength—ready to dig, lift, and load for years to come.