AxleTech 300, 400, 500 Series Differential Carrier Field Maintenance Manual
This maintenance manual provides comprehensive instructions for the service and repair of AxleTech International 300, 400, and 500 Series Single Reduction Carriers. These heavy-duty carriers are utilized in planetary axles and may include a Driver-Controlled Main Differential Lock (DCDL).
1. Key Technical Specifications
Accurate assembly and adjustment are critical for operational life:
- Pinion Bearing Preload: This is controlled by the thickness of the spacer between the bearings. For new bearings, the 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: The standard specification is 15–35 lb-in (1.7–3.9 N·m). Preload can also be measured by expansion between bearing caps: 0.002–0.009 inches (0.05–0.229 mm) for 300/400 series and 0.006–0.013 inches (0.15–0.33 mm) for 500 series.
- Ring Gear Backlash: For gears with a pitch diameter of 17 inches or larger, the range is 0.010–0.020 inches (0.25–0.51 mm), with a nominal setting of 0.015 inches (0.38 mm) for new gear sets.
- Rotating Resistance: Differential gears should have a maximum rotating resistance of 50 lb-ft (68 N·m) torque applied to one side gear.
2. Core Assembly Procedures
- Matched Gear Sets: Drive pinions and ring gears are matched sets and must always be replaced together.
- Pinion Depth Adjustment: Controlled by a shim pack between the bearing cage and carrier. Technicians must calculate new shim thickness using measured old shims and Pinion Cone (PC) variation numbers die-cut on the gears.
- Ring Gear Installation: Ring gears must be heated in water to 160°F–180°F (71°C–82°C) for 10 to 15 minutes to permit a press-free fit over the case half pilot.
- Sealing: Use only approved silicone gasket material (e.g., Loctite 5699) in a 0.125-inch (3 mm) diameter bead around fastener holes.
3. Safety and Maintenance
- Carrier Removal (DCDL Models): Before removing or installing a carrier with a DCDL, the lock must be manually shifted into and held in the engaged position using a manual engaging capscrew to provide necessary clearance from the axle housing.
- Towing: Axle shafts must be removed before towing the vehicle with drive wheels on the ground to prevent internal damage.
- Lubrication: Use API GL-5 hypoid gear oil. Axle sump temperatures must never exceed 250°F (121°C).