AxleTech 500 Series Drop Gear Differential Carrier Field Maintenance Manual
This maintenance manual provides comprehensive instructions for the service and repair of AxleTech International 500 Series Drop Gear Differential Carriers. These heavy-duty carriers are designed for planetary axles and may include a Driver-Controlled Main Differential Lock (DCDL).
1. Technical Adjustments and Specifications
Precise technical settings are critical for the longevity and safety of the carrier.
- Pinion Bearing Preload: Controlled by a spacer between the bearings. For new bearings, the preload should be 15-25 lb-in (1.7-2.8 N·m); for used bearings, it is 5-25 lb-in (1.7-2.8 N·m).
- Differential Bearing Preload: The standard specification is 15-35 lb-in (1.7-3.9 N·m). It can also be measured by bearing cap expansion, with a target of 0.006-0.013-inch (0.15-0.33 mm) for 500 Series models.
- Ring Gear Backlash: For new gear sets, the backlash should be set to 0.015-inch (0.38 mm), within an allowable range of 0.010-0.020-inch (0.25-0.51 mm).
- Rotating Resistance: The differential gears should have a maximum rotating resistance of 50 lb-ft (68 N·m) applied to one side gear.
2. Core Maintenance and Assembly
- Matched Gear Sets: Drive pinions and ring gears are matched sets and must always be replaced together to prevent premature failure.
- Ring Gear Installation: Ring gears must be heated in water to 160°F-180°F (71°C-82°C) for 10 to 15 minutes before installation. They should never be pressed on cold, as this can damage the case half.
- Pinion Depth: Controlled by a shim pack between the bearing cage and the carrier. New shim thickness is calculated based on old measurements and the Pinion Cone (PC) variation numbers die-cut on the gears.
- Drop Gear Preload: Controlled by a spacer between the drop gear bearings. Preload should be 10-25 lb-in (1.1-2.8 N·m) for new bearings and 5-20 lb-in (0.6-2.3 N·m) for used bearings.
3. Safety and Operational Guidelines
- Carrier Removal (DCDL Models): Before removing or installing the carrier, the differential lock must be shifted and held in the engaged (locked) position using a manual engaging capscrew to provide necessary clearance from the axle housing.
- Towing: To prevent internal component damage, axle shafts must be removed before towing a vehicle with its drive wheels on the ground.
- Fluid Quality: Use only API GL-5 hypoid gear oil . The axle sump temperature must never reach or exceed 250°F (121°C), as this will damage internal components.