25153310
Drive Pulley
Mack

The drive pulley is a primary component in the accessory belt drive system, transferring rotational power from the crankshaft to alternators, compressors, and other driven accessories. Its groove count, bore size, and keyway arrangement determine belt alignment, tension distribution, and overall accessory performance. A well-designed pulley minimizes belt slip, reduces wear on the belt surface, and supports consistent RPM transfer to attached devices, which helps maintain electrical charging, cooling, and power steering efficiency. The pulley must tolerate operating temperatures, surface contamination, and vibration typical of heavy-duty trucking environments, all while maintaining precise alignment with the other pulleys and the belt. When selecting a replacement, verify that the pitch, profile, and mounting configuration match the original to prevent early belt failure and noise. Source One Parts Center.