A tandem-axle heavy-duty truck equipped with an inter-axle differential lock (IADL) engages in a low-traction situation. When the IADL is engaged, what is the immediate effect on power distribution between the front and rear drive axles?

Question: A tandem-axle heavy-duty truck equipped with an inter-axle differential lock (IADL) engages in a low-traction situation. When the IADL is engaged, what is the immediate effect on power distribution between the front and rear drive axles?

Answer options: ✅ It locks the differential, ensuring both axles receive equal torque regardless of traction differences, effectively bypassing the inter-axle differential action.

• It directs all power to the axle with the most traction, disengaging the axle with the least traction.
• It reduces the torque output to both axles to prevent wheel spin.
• It engages a secondary planetary gear set to multiply torque to both axles.

Correct answer: It locks the differential, ensuring both axles receive equal torque regardless of traction differences, effectively bypassing the inter-axle differential action.

Explanation: Engaging the inter-axle differential lock bypasses the differential action, mechanically coupling the output shafts of the inter-axle differential. This forces both axles to rotate at the same speed, ensuring both receive torque to help in low-traction conditions.