Complete modular 9" aluminum housing with steel end bells welded to 3" x .250" chromoly steel tubes. Aluminum through bolt case, steel 4-Link brackets, with tie bar, 40-spline flange axles, wheel bearings, drive stud set, standard with a lightweight steel spool (optional 35-spline Detroit Truetrac or Detroit Locker available), 9" large pinion pro gear, ball / taper bearing pinion support, 4340 pinion yoke, 1350 series U-joint, MW steel disc brakes featuring drilled rotors and quick change 4-piston calipers. Any housing width and 4-Link center measurement.