FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly: Why These 46 Critical Parts Are Essential

Welcome to this critical technical guide on the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly. This is the complete “differential carrier” or “pumpkin” assembly (Part No. 2502010QA6T) for the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor.

This FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly is the “brain” of the drive axle. It has three vital functions: the ‘Gearbox Housing’ contains the components; the ‘Drive Bevel Gear’ (ring and pinion) provides the final gear reduction (io=2.867); and the ‘Inter-Wheel Differential And Differential Lock Logic Assembly’ manages traction, allowing wheels to spin at different speeds or locking them together.

This in-depth guide is an essential resource for professional driveline technicians. We will deconstruct the entire FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly into its 46 serviceable components, including the main housing, the gearset, the pneumatic differential lock mechanism, all bearings, and the critical “as-needed” shims.

The “Gearbox Housing” (2502015-A6T)

The “Gearbox Housing” component of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly is the ‘Centre axle reduction gearbox housing assembly’ (2502015-A6T). This is the main “carrier” or “pumpkin,” a massive, heavily-ribbed casting of ductile iron.

This housing (2502018-A6T) is the skeleton that holds all other components in perfect alignment. It is precision-machined with bores to hold the main differential carrier bearings and the pinion shaft bearings. These bores are secured by the ‘Reducer bearing cap’ (2402019-A6T) and ‘Reducer bearing cap’ (2402024-1H), which are line-bored as a matched set.

The integrity of this FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly housing is critical. It must maintain the precise “mesh” between the ring and pinion gear, down to a few thousandths of an inch. Any failure here will destroy the gearset.

The “Drive Bevel Gear” (Pinion) and Reduction (io=2.867)

The “Drive Bevel Gear” is the ‘Pinion shaft assembly’ (2502036EA6T). This is the “pinion gear” that receives power from the driveshaft. It is paired with the ‘Main driven bevel gear’ (2502108-A6T), or “ring gear.”

The ‘Centre axle reduction gearbox assembly (io=2.867)’ (2502010QA6T) specifies the critical “logic” of this FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly: the **io=2.867** gear ratio. This means the driveshaft (pinion) must turn 2.867 times to make the ring gear (and wheels) turn once. This is the final torque multiplication.

This ‘Pinion shaft’ is supported by two massive ‘Tapered roller bearing assembly’ units (2402060-A8T-C00 and 2402050-A8T-C00). The ‘Nut-pinion shaft bearing’ (2402069-A0E) is used to set the “preload” on these bearings. This entire sub-assembly is a core part of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly.

The “Inter-Wheel Differential” (2503010QA6T)

The ‘Centre axle differential assembly (io=2.867)’ (2503010QA6T) is the “Inter-Wheel Differential.” This is the set of “spider” and “side” gears (not individually listed, but part of this assembly) housed *inside* the ‘Reducer housing’.

This is the “logic” that allows the truck to turn a corner. When driving straight, this unit spins as a solid block, sending equal torque to both wheels. When turning, the inner wheel slows down, and this forces the “spider” gears to “orbit,” which in turn *accelerates* the outer wheel. This differentiation is essential to prevent “axle bind” and tire scuffing.

The entire FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly is supported in the main housing by the ‘Differential bearing’ (2403071AA6T), which is a large tapered roller bearing.

The “Differential Lock Logic Assembly”

The final “logic” of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly is the “Differential Lock.” This system *overrides* the differential logic for high-traction situations.

This system is pneumatically (air) operated. It includes:

• ‘Air cylinder’ (2406016-A6T) with its ‘Cover’ (2406017-A0E), ‘Piston’ (2406013-A0E), and ‘Seals’ (2406019-B4A, 2406014-A0E).
• ‘Fork assembly’ (2406025-A3C) and ‘Fork’ (2406024AA6T).
• ‘Inter-wheel differential lock sliding gear’ (2406032AA6T).

When the driver flips the “diff lock” switch, air enters the ‘Air cylinder’, pushing the ‘Piston’. This moves the ‘Fork’, which slides the ‘Sliding gear’ over a set of dog-teeth. This action *physically locks* one of the axle-shaft “side gears” to the differential case. This forces both wheels to spin at the same speed, providing 100% torque to both wheels, even if one is on ice. The ‘Return spring’ (2406028-A0E) disengages the lock when the air is released. The ‘Inter-wheel differential lock switch assembly’ (3834050-A0E) is the sensor that tells the ECU the lock is engaged. This is a critical part of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly.

Shims, Bearings, and Fasteners

The long-term survival of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly depends on its “shimming.” The parts list details a large number of ‘Adjustment gaskets’ and ‘Adjustment rings’ (2402097-A6T, 2402098-A6T, 2402099-A6T, 2402088D1HB2, etc.).

These “as needed” (按需) shims are used by a technician to set the **bearing preload** (the “squeeze” on the tapered bearings) and the **gear backlash** (the tiny gap between the ring and pinion teeth). This is the most complex part of assembling a FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly. Using the wrong shim will destroy the bearings or gears.

The assembly is held together by a vast array of high-tensile ‘Hex flange bolts’ (Q1851640TF2K, Q1851665TK, Q1841060S) and ‘Hex head bolts’ (CQ15022130TF2K). The ‘Inner hex tapered magnetic screw plug’ (T62104M) is the drain plug, which is a key diagnostic part of the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly.

FAW Gearbox Housing… Logic Assembly Parts List (1/2)

The following table provides the first part of the detailed breakdown for the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly.

FAW Gearbox Housing… Logic Assembly Parts List (2/2)

This table details the remaining components for the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly.

Technical Specifications and Assembly Context

The specifications for the FAW Gearbox Housing, Drive Bevel Gear, Inter-Wheel Differential And Differential Lock Logic Assembly are defined by its dual function as a final-drive reduction gear and a pneumatically-actuated differential lock.