CT681

A natural extension of the Cat® product line, the Cat CT681 Vocational Truck delivers all the power, performance and productivity you expect from Caterpillar. This Class 8 set-forward axle model—ideal for hauling heavy loads—features a spacious and ergonomic cab, industrial styling, vocational-specific engine and transmission options, and bumper-to-bumper support across North America.

Engine

Engine Model
Cat® CT13 Engine
Horsepower @ 1700 rpm
365 - 430 hp (268 - 316 kW)
Bore
4.96 in
Engine Type
Diesel, 4-Cycle
Configuration
Inline 6-Cylinder
Stroke
6.54 in
Compression Ratio
17:1
Displacement
758.0 in3
Aspiration
Dual Series Turbochargers, Intercooler and Aftercooler
Combustion System
Direct Injection
Lubrication System Capacity
42.0 qt
Coolant Drain Interval
600,000 miles (965,606 km)
Total Engine Weight (Dry)
2400.0 lb
Width
37.0 in
Length
59.0 in
Height
49.0 in
Valves
4 Valves Per Cylinder, Overhead Cam Actuated
Peak Torque @ 1000 rpm
1550 lb-ft (2102 N-m)

Transmission

Maximum Gross Input Power
550.0 hp
Maximum Gross Input Torque
1700.0 lb ft
Transmission Model
Cat CX31® Automatic Transmission
Speeds
6 forward/1 reverse
Torque Converter:
Cast aluminum design with lock up clutch
Clutches:
Electro-hydraulic fully modulated, oil cooled, multidisc
Maximum Input Speed:
2500 rpm
Length
35.3 in
Overall Length with Retarder Option
39.4 in
Overall Weight (approx.)
906.0 lb
Overall Weight with Retarder Option
1088.0 lb
Power Take-Off
Two side locations and a Cat exclusive high output rear PTO
Rear PTO Capacity (rotation opposite of engine, at 1.25 engine speed)
800.0 ft-lb
Side PTO Capacity (rotation same as engine, ratio determined by PTO adaptor)
700.0 ft-lb
  • Chasis
    • Set-forward axle, 114-inch bumper to back of cab (BBC)
    • 12.25-inch rail size: 120,000 psi yield strength
    • Above-rail radiator
  • Axles
    • Meritor & Dana options
    • 6x4 truck configuration
  • Front Suspension
    • Parabolic taper leaf for a smoother ride
    • Shock absorbers standard
    • Optional two-stage, multi-leaf, shackle-type with shocks
  • Rear Suspension
    • Hendrickson offerings: HMX, RT/RTE, RS, R & PriMaax
    • Chalmers standard & high articulation
    • Capacities from 40,000-85,000 lbs.
  • Fuel Tank
    • 80-, 100- & 120-gallon capacities
    • Single left or dual under cab/back of cab options
    • Aluminum alloy construction
  • Chassis
    • Integral Front Frame Extension (FFE)
  • Transmission
    • Cat CX31 Automatic Transmission
    • A variety of manual transmissions and the Ultrashift® Plus Vocational Transmission built by Eaton
  • On-Board Technology
    • Vehicle Infotainment System
    • Bendix Tire Pressure Monitoring System