Ford 1C2Z-4209-FA
Ring & Pinion

The first step involves match-marking the differential case flange and button halves and the differential pinion shafts together with their corresponding ramps before starting Model 70 Limited Slip differential case and ring gear service work. The differential ring gear should be removed only if needed. The differential case can be properly held through the use of an installed axle shaft in a vise whose splines must not reach beyond three inches above the jaws. Place the differential assembly on a bench after loosening its bolts but leave the bolts in position and remove the bolts as well as the button half of the differential case. Separate and carefully organize the differential side gear together with side gear ring and rear axle disc and plate kit and differential pinion gears and pinion shafts for correct assembly. Put together the pinion flange assembly by placing the side gear ring and rear axle disc and plate kit received from the flange half of the differential case. Check the clutch plates and discs for cracks, excessive wear and distortion before installing new rear axle disc and plate components on each side whenever you discard any clutch plates or discs. Thorough inspection must include an assessment of the differential pinion shafts alongside ramp surfaces and a close look at the side gear together with its pinion gear teeth and side gear races for both wear and damage. Friction modifier should be used to soak each clutch pack component for a period of twenty minutes before assembly. Set the side gear ring inside the pinion flange before applying lubricant to both the rear axle disc and plate kit while positioning it onto the side gear ring. Examine that the gear splines on the side component correctly link to clutch pack splines when the differential side gear reaches complete insertion. Place the side gear ring and rear axle disc and plate kit together with the side gear within the differential case flange half. Vehicles operating near GVW may need to combine rear axle disc and plate with the clutch disc adjacent to the differential side gear ring to create two clutch plates which decrease wheel rotational torque by 40 percent. The clutch press plate lugs need alignment before installing the side gear ring along with clutch pack and differential side gear inside the button half of the differential case. Property marks established during dismantling should guide you when placing differential pinion shafts and gears into both pieces of differential case housing. The button half of the differential case requires placement onto the flange half with proper attention given to clean dry bolts before installation. Equal and alternating steps should be used when bolting. Each differential pinion shaft fits properly on its ramp so that clearance should not exceed 0.254 mm (0.010 inch) measurements at all four ends. Reinstall the differential ring gear before tightening its Grade 9 bolts to 176 Nm (130 ft. lbs.).

Consult the differential case and ring gear.