Which of these is not commonly a part of the power transmission system?

• A. Chassis
• B. Gears
• C. Shafts
• D. Belts

Answer: (A)

The important idea is what actually carries power from the engine to the wheels. Gears, shafts, and belts are all parts that transfer or modify that power along the drive path, changing torque and speed as needed. Gears form gear trains to adjust ratios, shafts carry the rotating power between gears and to the wheels, and belts (with pulleys) transmit motion when a direct gear mesh isn’t used.

The chassis, on the other hand, is the vehicle’s structural frame. It supports and mounts components but does not participate in transmitting torque or altering power flow. So while the transmission may be mounted to the chassis, the chassis itself isn’t a functional part of the power transmission system.