X0X
X0X: Cab, Climate, and Control Devices
- 001 Air Conditioning, Heating, and Ventilating System
- 002 Cab and Sheet Metal
- 003 Instruments, Gauges, and Meters
- 004 Aerodynamic Devices
X1X
X1X: Chassis
- 011 Axles Front—Non-Driven
- 012 Axles Rear—Non-Driven
- 013 Brakes
- 014 Frame
- 015 Steering
- 016 Suspension
- 017 Tires
- 018 Wheels, Rim, Hubs, and Bearings
- 019 Automatic/Manual Chassis Lubricator
- 111 Undercarriage
- 112 Stabilization
X2X
X2X: Drivetrain
- 021 Axle Driven—Front Steering
- 022 Axle Driven—Rear
- 023 Clutch
- 024 Drive Shaft(s)
- 025 Transfer Case
- 026 Transmission—Main, Manual
- 027 Transmission—Main, Automatic
- 028 Transmission—Auxiliary and Transfer Case
- 029 Auxiliary Section (Transmission—Main, Manual)
X3X
X3X: Electrical
- 031 Charging System
- 032 Cranking System
- 033 Ignition System
- 034 Lighting System
X4X
X4X: Engines
- 041 Air Intake System
- 042 Cooling System
- 043 Exhaust System
- 044 Fuel System
- 045 Power Plant
- 046 Electric Propulsion System
- 047 Filter Kits (Multi-Piece)
X7X
X7X: Bodies & Vessels
- 071 Body (except bulk carrier body)
- 072 Rear Wall and Door
- 073 Tank Vessel, inner shell
- 074 Tank Vessel, outer jacket
- 075 Manholes
- 076 Rings and Bolsters
- 077 Trailer Frame and Support
- 078 Trim and Miscellaneous Hardware
- 079 Safety Devices
- 171 Mixers
- 172 Compaction Bodies
- 173 Tilt Bodies
X9X
X9X: Bulk Product Transfer
- 091 Blowers, Conveyors & Vibrators
- 092 Compressor
- 094 Lines, Tubes, Hoses, and Fittings
- 095 Manifold
- 096 Power Shaft
- 097 Pump
- 098 Valves and Controls
- 099 Safety Devices, Instruments and Gauges