John Deere 300D Backhoe Loader – Parts, Specs & Serial Numbers

The John Deere 300D Backhoe Loader is a durable, mid-sized machine popular among utility contractors and municipalities for its solid frame, dependable drivetrain, and balanced loader-backhoe capabilities. Built in the 1980s and 1990s, the 300D features mechanical simplicity, making it easy to maintain and service. While not as technologically advanced as newer models, its reliable components and easy-to-source parts make it a go-to workhorse on job sites.

Specifications:

Engine

• Engine Model: John Deere 4239D

• Type: 4-cylinder, naturally aspirated diesel

• Displacement: 239 cu in (3.9 L)

• Net Power: 62 hp (46.2 kW) @ 2,500 rpm

Transmission

• Type: Collar shift (manual)

• Gears: 8 forward / 4 reverse

• Clutch: Dry disc

• Max Speed: Approx. 20 mph (32 km/h)

Hydraulic System

• System Type: Open center

• Pump Flow: 24 GPM (90.8 L/min)

• System Pressure: 2,250 psi (155 bar)

Backhoe Specifications

• Max Digging Depth: 14 ft (4.27 m)

• Loading Height: 11 ft (3.35 m)

• Bucket Digging Force: ~9,800 lbf (43.6 kN)

• Swing Arc: 180°

Loader Specs

• Lift Capacity at Full Height: ~4,200 lbs (1,905 kg)

• Bucket Width: 72–84 in (1.83–2.13 m)

• Breakout Force: Approx. 6,000 lbf (26.7 kN)

Dimensions & Weight

• Operating Weight: ~13,000 lbs (5,900 kg)

• Overall Length: 23 ft 2 in (7.06 m)

• Wheelbase: 81 in (2.06 m)

• Height to Top of ROPS: 9 ft (2.74 m)

Maintenance Essentials:

• Engine Oil/Filter: Replace every 100–150 hours

• Hydraulic Filter & Fluid: Replace every 500 hours or when contaminated

• Commonly Replaced Parts:

  • Backhoe cylinder seal kits

  • Brake shoes and linkage kits

  • Loader pins and bushings

  • Water pumps and fan belts

Common Issues & Quick Fixes:

• Brake Fade or Failure: Caused by worn drum brakes or linkage rust. Solve with complete brake rebuild kits.

• Hydraulic Leaks: Typically from aging seals — boom, dipper, and loader arms.

• Shifting Difficulty: Linkage wear or dry clutch — inspect shift forks, and use replacement clutch assemblies.

Pro Tips:

• Frequently grease all pivot points to extend pin and bushing life.

• Clean the radiator fins regularly to prevent overheating — the 4239D runs hot under load.

• Install a magnetic drain plug to monitor early signs of transmission wear.

Serial Number Info:

• Serial number is stamped on a metal tag located on the left side of the machine frame, near the loader tower or engine block.

• Serial number format: typically begins with T0300D_ _ _ _ _ _

• Always check the serial number before ordering model-specific components.