In a gearbox, what is a common effect of gear wear?

• A. Increased backlash, noise, vibration, and reduced efficiency.
• B. Decreased backlash
• C. Increased efficiency
• D. No change

Answer: (A)

When gears wear, the clearance between meshing teeth grows, so backlash increases. That extra play means the teeth don’t stay in constant contact, especially under load, which leads to more intermittent contact, resulting in higher noise and vibration. The worn surfaces also don’t transmit power as cleanly, so sliding losses rise and energy is wasted as heat, which lowers overall efficiency. In short, wear makes the gear mesh looser, noisier, rougher, and less efficient.