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300-4009ST

STEMCO HUB CAP

This is a Stemco cast aluminum hub cap for heavy-duty truck or trailer drive axles with a TN axle bolt pattern. It seals the wheel hub to keep gear oil in and dirt, water, and debris out, protecting bearings and axle components. The 300-4009ST variant includes a side fill plug, which allows you to check and top off hub oil without removing the center fill plug. Hub caps are typically replaced when they become damaged, start leaking, or during routine wheel‑end service to prevent expensive axle damage.