1973 Mercury Comet Differential Carrier Yukon Dura Grip - Ford 9 in. Rear - 28 Spline - Limited Slip - 4 Spring Aggressive Setup - May Chatter - Requires Longer Trac-Loc Bolts - 1.78 in. Bearing Journals - Rear guaranteed to replace your current 1973 Mercury Comet Differential Carrier Yukon Dura Grip - Ford 9 in. Rear - 28 Spline - Limited Slip - 4 Spring Aggressive Setup - May Chatter - Requires Longer Trac-Loc Bolts - 1.78 in. Bearing Journals - Rear. 1973 Mercury Comet Differential Carrier comes new OEM 1973 Mercury Comet Differential Carrier aftermarket new 1973 Mercury Comet Differential Carrier of remanufactured 1973 Mercury Comet Differential Carrier Yukon Dura Grip - Ford 9 in. Rear - 28 Spline - Limited Slip - 4 Spring Aggressive Setup - May Chatter - Requires Longer Trac-Loc Bolts - 1.78 in. Bearing Journals - Rear.