Agricultural vehicle with debris-purging clutch assembly

A header for an agricultural vehicle, comprising:

• a header frame;
• a gearbox carried by the header frame;
• and
• a clutch assembly comprising:
• a drive hub comprising a spline coupled to the gearbox;
• a clutch housing coupled to the drive hub and comprising an end face defining an opening therein;
• a clutch hub disposed within the clutch housing and comprising a portion that extends out of the opening, the clutch hub being rotatable with respect to the clutch housing during a slip condition;
• a primary seal disposed between the clutch housing and the clutch hub;
• a quantity of purging compound disposed between the clutch housing and the clutch hub;
• and
• an end washer coupled to the clutch hub and facing the end face, the end washer and the end face defining a purge gap therebetween such that rotation of the clutch hub relative to the clutch housing causes some of the purging compound to eject from the clutch housing through the purge gap.