Red Seal Truck and Transport Mechanic Practice Exam

What is the function of the differential in a truck?

1. To ensure equal power distribution to all wheels

2. To allow for differences in wheel speed between the left and right wheels during turns

3. To assist in the braking process during a collision

4. To enhance traction on slippery surfaces

The correct answer is: To allow for differences in wheel speed between the left and right wheels during turns

The function of the differential in a truck primarily focuses on allowing for differences in wheel speed between the left and right wheels during turns. When a vehicle makes a turn, the wheels on the outside of the turn travel a greater distance than those on the inside. Without a differential, both wheels would rotate at the same speed, potentially leading to tire slippage, increased tire wear, and instability while turning. The differential enables each wheel to rotate at different speeds while still transferring engine power effectively to both wheels. This coordination is crucial for maintaining control and stability, particularly in larger vehicles like trucks, where the dynamics of turning can be more pronounced due to their size and weight. While other choices present functions that might seem relevant to a vehicle’s performance, they do not accurately describe the unique role of the differential. For instance, ensuring equal power distribution is a characteristic of the overall drive system, while enhancing traction on slippery surfaces typically involves other mechanisms, such as traction control systems or different tire designs. Similarly, assisting in the braking process during a collision is related to braking systems rather than the differential's primary purpose.