Related Clues:

• Shifting things
• A ten-speed has ten
• They're shifted
• Transmission units
• Swiss watch parts
• Meshing parts
• Car-transmission settings
• First, second, etc.
• Bicycle parts
• They often get engaged
• Four-on-the-floor options
• Gets ready, with 'up'
• Neutral and reverse
• Transmission components
• Transmission settings