Hawks 8.8 Rear End 31 Spline Differential, Trac-Loc This is an OEM style genuine AAM Traclock posi differential. This fits all Ford 8.8 differentials with 31 spline axles. These are a rebuildable clutch style posi. NOTE: REQUIRES FRICTION MODIFIER. MSRP: Was: Price: Now: $269.99 Quick view View Options SKU: AL3Z4026A