This maintenance manual (MM5.1) provides comprehensive service and repair procedures for AxleTech Single Reduction Curvic Coupling Differential Carriers, specifically models RS-160 and RS-180. These carriers are equipped with a Driver-Controlled Main Differential Lock (DCDL), which uses a hydraulic shift assembly to lock the axle shafts together, eliminating differential action for improved traction .

1. Technical Adjustments and Specifications

Critical adjustments for assembly include:

Pinion Bearing Preload: Controlled by spacers between bearings. For new bearings, preload should be 15-25 lb-in (1.7-2.8 N·m); for used bearings in good condition, it is 5-25 lb-in (1.7-2.8 N·m).
Differential Bearing Preload: Standard specification is 15-35 lb-in (1.7-3.9 N·m). It can also be measured by expansion between bearing caps: 0.002-0.009-inch for RS-160 and 0.006-0.013-inch for RS-180.
Ring Gear Backlash: For gears with a pitch diameter of 17 inches or greater, the range is 0.010-0.020-inch, with a nominal setting of 0.015-inch for new gear sets.
Rotating Resistance: The differential gears should exhibit a maximum rotating resistance of 50 lb-ft (68 N·m) when torque is applied to one side gear.

2. Assembly and Disassembly Highlights

Pinion Depth: Pinion depth is controlled by shims between the bearing cage and the carrier. Technicians must calculate new shim pack thickness based on measured old shims and Pinion Cone (PC) variation numbers die-cut on the gears .
Matched Sets: Drive pinions and ring gears are matched sets and must always be replaced together .
Ring Gear Installation: The ring gear should be heated in water to 160°F-180°F (71°C-82°C) for 10-15 minutes to allow it to fit easily onto the case half without pressing.
Seal Installation: Unitized pinion seals require a specific driver (e.g., R4422402 for RS-160/180) to ensure they are seated correctly without a gap exceeding 0.010-inch .

3. Lubrication and Maintenance

Oil Specifications: Recommended gear oils include API GL-5 with viscosities such as 80W/90 or 75W/140 depending on the ambient operating temperature.
Change Intervals: For construction or heavy-haul vocations, petroleum-based oil should be changed every 25,000 miles or annually; synthetic oil intervals can extend up to 100,000 miles.

4. Safety and Towing

Caging the DCDL: Before removing or installing the carrier, the DCDL must be shifted and held in the engaged position using a manual engaging capscrew to provide necessary clearance
Towing: To prevent component damage, axle shafts must be removed before towing the vehicle with the drive wheels on the ground