Related Clues:

• Assembly line add-on, perhaps
• Highway toll unit
• It may have a linchpin
• Wheel connection
• Item involved in a tire change
• Drivetrain connection
• Wheel supporter
• Revolutionary car part?
• A semi lacks a front one
• Shaft under the floorboard
• Fastener that's actually easy to pick up and carry?
• Drivetrain component
• Bar between Pirellis
• Linchpin's setting
• One of two on a car