Ford 9L3Z-4204-A
Differential Case, Front

Service and repair of the differential case and ring gear for Model 70 with limited slip demands an initial step where technicians should create match marks on the differential case flange and button halves together with the differential pinion shafts and corresponding ramps. In some cases you should remove the differential ring gear. A differential case can be effectively held in place using a vise which holds one axle shaft when its splines extend only three inches above the jaws. Leave the bolts in place but untighten them before setting the differential assembly on a bench. Remove both the bolts and button half of the differential case. Separate and prepare the differential side gear with side gear ring alongside the rear axle disc and plate kit and differential pinion gears as well as pinion shafts for later reinstallation. The flange half of the differential case requires extraction of its side gear ring and rear axle disc and plate kit which will be set on the pinion flange to maintain order. Check for damage and wear patterns in all clutch plates and discs and inspect both differential pinion shafts as well as the ramp surfaces and side gear teeth and races. Prior to assembling the clutch packs allow them to soak in Additive Friction Modifier C8AZ-1913546-A along with equivalent products for 20 minutes. The pinion flange should receive the side gear ring while the rear axle disc and plate kit needs a lubricant layer before placement on the side gear ring with SAE 80W-90 Premium Rear Axle Lubricant XY-80W90-QL or equivalent product. The installation process requires verifying complete side gear spline engagement with clutch pack splines and full side gear positioning inside the flange half of the differential case before side gear ring along with the rear axle disc and plate kit and side gear installation. It is necessary to place the rear axle disc and plate kit with its clutch disc situated next to the differential side gear ring when vehicles approach their gross vehicle weight rating to achieve three contact surfaces instead of five providing 40 percent wheel rotation torque reduction. Mount the side gear ring followed by the clutch pack at the button half part of the differential case together with the differential side gear. Both differential pinion shafts and gears need to be inserted into the halves of the differential case after aligning the disassembly match marks. After inspecting all bolts for dry and clean conditions install the button half onto the flange side of the differential case. Evenly distribute torque when securing the bolts while alternating between them. Klamia differential pinion shaft assembly will achieve proper communication with its ramp while maintaining 0.254 mm (0.010 inch) maximum gap across the four connection points. Attach the differential ring gear and tighten Grade 8 bolts to 176 Nm (130 ft. lbs.) while Grade 9 bolts need a torque setting of 298 Nm (220 ft. lbs.).

Fill the rear axle housing with 2.37 liters (5 pints) of the specified lubricant.

Detach the rear disc brake caliper and wire it aside before removing the rear brake disc.

Ensure the electrical power to the air suspension system is turned off by switching off the air suspension switch located in the RH kick panel area.

Drain the lubricant and remove the brake calipers and discs.