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• Manufacturer:
  Astec Underground
• Model:
  RT660

Maximum Trencher Dig Depth: 72" (1.83 m)
Trenching Widths: 6-16" (152-406 mm)

Gross Horsepower: 67 hp (50 kW)

Overall Width: 71" (1.8 m)
Operating Weight: 10,304 lbs (4674 kg)

ENGINE
Model: Cummins
Type: 4-stroke, naturally aspirated
Cylinders: 4
Bore/Stroke: 4.02" x 4.72" (102 x 120 mm)
Displacement: 239 in3 (3.9 L)
Fuel injection: Direct
Fuel: Diesel
Fuel filter: Spin-on cartridge
Air intake: Cross-flow
Cooling: Liquid

Horsepower -
Gross:67 (50 kW) @ 2200 rpm
Net: 63 (47 kW) @ 2200 rpm

Maximum torque -
Gross: 188 ft/lbs (255 Nm) @ 1200 rpm
Net: 185 ft/lbs (251 Nm) @ 1200 rpm

ENGINE COOLING
Radiator -
Core type: Square wave
Core size area: 397 in2 (0.39 m2)
Rows of tubes: 4
Fan with standard transmission -
Style: 7 blade suction
Diameter: 17.8" (452 mm)
Ratio: 1.1:1
Water pump Style: Integral
Engine oil Pump: Deep sump, plate cooler with pressurized nozzles under-piston
Pump operating angle ratings -
Side-to-side: Rated 45°
Fore and aft: Rated 45°
Oil filtration: Spin-on, full-flow cartridge

POWERTRAIN
Transmission: Hydrostatic 4WD with 4-wheel steering. Limited-slip differential and outboard planetaries on both front and rear axles. Modular powertrain components.
Drive: Hydrostatic variable displacement axial-piston pump 0 – 36 gpm (0-137 L/min)
U-joints: Constant velocity
Axle ratio: 11.6:1
Planetaries: 6:1 – Outboard
Differentials: Limited slip
Steering: 2W, 4W and crab
Axle oscillation: 20°
Service brakes: Hydrostatic
Parking brake: Foot applied disc

Travel speeds (m.p.h.)
Tires: 31 x 15.5-15: First: 1.4, Second: 1.9, Third: 5.1, Fourth: 7.4
Tires:35 x 19-16.1: First: 1.4, Second: 1.9, Third: 5.1, Fourth: 7.4
NOTE: Rated speeds in forward and reverse

TIRES
31 x 15.5 - 15, 8 PR
35 x 19 - 16.1, 12 PR (heavy-duty)

SERVICE CAPACITIES
Fuel tank: 17 gal (64.4 L)
Cooling system: 18 qt (17 L)
Engine with oil filter: 11.6 qt (11 L)
Pump drive: 1.4 pt (0.65 L)
Hydraulic reservoir: 14 gal (53 L)
Total hydraulic: 20 gal (75.8 L)
Transmission: 1.8 qt (1.7 L)
Axle center (each): 4 qt (3.8 L)
Planetaries (each): 0.65 qt (0.6 L)
Trencher planetary drive: 1.5 qt (1.4 L)
Hydra-Borer System: 1.0 qt (0.9 L)

HYDRAULICS
Attachment drive pump: 36 gpm (137 L/min)
Steering pump: 8.6 gpm (32 L/min)
Accessory pump: 8.6 gpm (32 L/min)
Filtration:
Full-flow spin-on cartridges
Accessory return: 2 micron
Charge pump flow (2): 2 micron
NOTE: Pump capacity rated @ 2200 engine rpm

ELECTRICAL SYSTEM
Voltage: 12 volts, negative ground
Alternator: 65 amp
Starter: 2.5 kW (3.35 HP)
Battery: 685 cold-cranking amps

OPERATOR ENVIRONMENT
ROPS
Left and right entry/exit
Unobstructed operator platform
Swivel seat with seat belt
Key start
Hand and foot travel controls
Adjustable and rotating seat position

INSTRUMENTATION
Engine coolant temperature gauge
Hydraulic oil temperature gauge
Fuel level indicator
Voltage meter
Engine oil pressure indicator
Tachometer/hourmeter
Hydraulic charge filter indicator
Hydraulic filter indicator
Air filter restriction indicator
Neutral indicator
Alternator light
Park brake light