43RU48M
Spacer Sleeve
Mack

Spacer Sleeve is a cylindrical component used to position and maintain precise clearance between mating parts in axles, steering linkages, or frame bushings. This hardened sleeve bears the load, aligns components, and reduces wear by providing a consistent bore-to-shaft gap. In heavy-duty truck assemblies, small misalignments can cause uneven load distribution, premature bearing wear, or vibration-induced fatigue. The sleeve isolates components, accommodates tolerances, and helps preserve correct geometry after maintenance or replacement. When installed with proper torque on the related fasteners, it helps ensure the correct clamping force and minimizes fretting and galling under harsh highway conditions. It is designed to slip into a bore and act as a durable spacer compatible with standard diameters, simplifying alignment during service. By maintaining uniform gaps, it supports even lubrication, reduces heat buildup at interfaces, and extends component life. For maintenance crews, this part provides a predictable, repeatable foundation for reliable assembly. Source One Parts Center.