John Deere 644K » Harvest Equipment and Theriault Equipment

John Deere 644K

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  • 644K Hybrid delivers up to 25-percent better average fuel efficiency than its conventional IT4 counterpart with a lockup torque converter. In applications such as V-pattern truck loading, fuel savings will be even larger.
  • EPA IT4/EU Stage IIIB 6.8-L diesel runs at a constant 900, 1,200, 1,500, or 1,800 rpm. Constant speed reduces engine wear, noise levels, and fuel consumption. Top speed provides maximum power and productivity, while the slower settings increase efficiency.

Hybrid-Electric Drive

  • Hybrid-electric drive smoothly and efficiently recaptures energy to slow the loader when the operator lets off the accelerator. This lessens the load on the engine and reduces fuel consumption.

Nevergrease™ Pin Joints

  • The NeverGrease™ option includes a pin-joint system for the linkage and boom joints that eliminates greasing, extends pin-joint life, and provides consistent life across the system.


  • Quad-Cool places the radiator, air-conditioner condenser, intercooler, and hydraulic, transmission, and optional axle coolers in a unique boxed configuration that's isolated from engine heat.


  • PowerShift™ transmission provides smooth moves through four forward speed ranges.


  • All daily service points, including fuel, are grouped on the left side for quick and convenient ground-level access. Sight gauges enable quick fluid-level checks.


  • Equip your loader with optional Z-Bar, High Lift, Tool Carrier, or Parallel Lift linkages.
  • Worksite Pro couplers make attachment switchover easy to get even more out of your machine.

Safety & Security

  • Sealed-switch module keeps out dust and moisture while eliminating nearly 100 wires. Prevent unauthorized machine operation with keyless-start requiring a numeric pass code.
  • Optional rearview camera and radar object-detection system


MODEL John Deere 644K Wheel Loader
Engine Manufacturer John Deere
Engine Model PowerTech PSS 6090
Emission Rating Tier 4
Displacement, ltr (Inches) 9 (548)
Rated Speed, rpm 1700
Engine Output - Net, kW (hp) 173 (232)
Torque, Nm (lbf / ft) 1062 (783)
Torque Rise, % 56
Transmission Type Powershift
Front Differential Type Locking
Rear Differential Type Open
Tire size - Standard 23.5 R25
Service Brake - Type Wet Disc
Service Brake - Location Axle Inboard
Service Brake - Actuation Hydraulic
Parking Brake - Type Wet Multi Disc - Transmission
Height - Over Cab, mm (ft/in) 3430 (11 ft 3 in)
Wheelbase, mm (ft/in) 3260 (10 ft 8 in)
Length - Including Bucket, mm (ft/in) 8300 (27 ft 3 in)
Ground clearance, mm (inches) 461 (18.1)
Width Over tires - Std, mm (ft/in) 2875 (9 ft 5 in)
Height - Pivot Pin, mm (ft/in) 4120 (13 ft 6 in)
Reach - At 2130mm 45 Dump, mm (ft/in) 1610 (5 ft 3 in)
Turning Circle - Maximum, mm (ft/in) 13280 (43 ft 7 in)
Fuel Tank, ltr (gallons (US)) 397 (105)
Hydraulic Tank, ltr (gallons (US)) 105.2 (6.95)
Axle - Front, ltr (gallons (US)) 22 (5.75)
Axle - Rear, ltr (gallons (US)) 22 (5.75)
Transmission, ltr (gallons (US)) 23 (6)
Heaped Capacity, m (yd) 3.2 (4.25)
Bucket Capacity - Smallest, m (yd) 3.1 (4)
Largest bucket capacity, m (yd) 3.2 (4.25)
Breakout - Bucket , kgf (lbf) 15378 (33903)
Ride Control System Optional
System Voltage, V 24
Alternator Output, Amp 130
Pump Type Piston
Pump Flow, lt/min (gallons (US) / min) 297 (78)
System Pressure, bar (PSI) 251.66 (3650)
Operating Weight, kg (lbs) 18682 (41188)
Dump Height, mm (ft/in) 2910 (9 ft 7 in)
Reach at Full Height, mm (ft/in) 1060 (3 ft 6 in)
Tipping Load - Straight, kg (lbs) 14771 (32565)

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