Which gear set carries the load and is most affected by load, thus most likely to wear under driving conditions?

• A. Ring gear and pinion gears
• B. Ring gear only
• C. Pinion gear only
• D. Spider gears

Answer: (A)

The gear set that carries the load is the ring gear and pinion gears. In a typical axle, torque from the driveshaft goes through the pinion gear and meshes with the ring gear, which is attached to the differential carrier. This pair is directly responsible for transmitting power to the wheels, so they experience the highest contact stresses and sliding during driving. That repeated load, especially under acceleration or heavy torque, leads to the most wear on these gears.

The spider gears, inside the differential, mainly handle distributing torque between wheels when they spin at different rates. They don’t bear the full drivetrain load like the ring and pinion pair, so they wear less under normal driving.