Central Bridge Drive Shaft: Deconstructing 10 Critical Parts for Ultimate Drivetrain Reliability

This technical guide provides a complete deconstruction of the Central Bridge Drive Shaft assembly for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck. We will analyze the 10 distinct types of serviceable components that create this critical link, which is essential for transferring torque from the inter-axle differential to the middle axle.

The Central Bridge Drive Shaft, also known as an inter-axle propshaft, is a high-speed, high-torque component. Its function is to connect the truck’s transfer case (or inter-axle differential) output to the input pinion of the first (middle) rear axle. This specific shaft is relatively short but must endure extreme angles and high rotational speeds, especially when the 6×4 axle lock is engaged. This deconstruction focuses on the serviceable units, providing a clear path for technicians to perform rebuilds and maintenance, which is crucial for maximizing vehicle uptime and ensuring the reliability of the tandem-axle system.

Core 1: The “Articulation” Logic (The Universal Joint Assemblies)

The U-joint is the component that allows the Central Bridge Drive Shaft to transmit power smoothly across constantly changing angles. This assembly uses two complete U-joints (one at each end), which are constructed from five key serviceable part types.

1. Component: ‘Cross and needle roller bearing assy’ (2205030B761) – Qty 2
This (Comp 5) is the core of the U-joint, often called the cross or spider. It includes four precision-ground trunnions (arms) and four pre-packaged needle roller bearing caps. These caps are pressed into the yokes and retain the grease that is critical for smooth, low-friction articulation. Failure of these bearings is a primary cause of Central Bridge Drive Shaft vibration.

2. Component: ‘Flange yoke’ (2205023B761) – Qty 2
This (Comp 2) is the flange that physically connects the U-joint to the vehicle’s flanges (e.g., at the inter-axle differential and the middle axle pinion). The Central Bridge Drive Shaft assembly requires two of these, one for each U-joint.

3. Component: Fastener Group (Q32914 & Q1851455T) – Qty 8 each
This group includes the ‘Type I non-metallic insert hex lock nut’ (Comp 1) and the ‘Hexagon flange bolt’ (Comp 3). This Fastener Logic is a safety-critical system. The non-metallic insert in the nut provides prevailing torque, preventing the bolts from vibrating loose. This is essential for a high-RPM component like the Central Bridge Drive Shaft.

4. Component: ‘Circlip’ (2205041-A0M) – Select 8
This (Comp 4) is a precision-fit circlip, or snap ring. The Bill of Materials (BOM) specifies ‘Select 8’ and lists multiple sub-part numbers (2205042-A0M, 2205043-A0M, etc.). This Selective Fit Logic is vital for assembly. A technician must select a circlip of a specific thickness to achieve the exact, minimal end-play for the U-joint bearing caps. Using the wrong thickness will lead to either immediate binding or premature failure from excessive movement.

Core 2: The “Length & Torque” Logic (The Shaft Body Assembly)

This group of components forms the main body of the Central Bridge Drive Shaft. It is responsible for handling the “plunge” (dynamic length change) as the axles articulate and for transferring the full torque load.

1. Component: ‘Rear axle drive shaft weld yoke, spline tube and yoke assy’ (2201015-51B) – Qty 1
This (Comp 8) is the primary structural component. It consists of the main driveshaft tube, which is permanently welded to a yoke at one end and a spline tube (an internal spline) at the other. This Welded Logic is a design choice for maximum strength and rigidity. The welds ensure the yokes and tube act as a single piece, allowing them to transfer immense torque without failure. This is the backbone of the Central Bridge Drive Shaft.

2. Component: ‘Spline shaft yoke assy’ (2205020B761) – Qty 1
This (Comp 6) is the ‘slip yoke’. It is a yoke (which holds the other U-joint) that is permanently attached to a matching external spline shaft. This external spline is designed to slide, or plunge, in and out of the spline sleeve (Comp 8).

This Plunge Logic is essential for a tandem-axle truck. As the axles articulate over uneven terrain, the distance between them and the transfer case changes. This slip-yoke assembly allows the Central Bridge Drive Shaft to change length dynamically. This prevents the assembly from binding and destroying the U-joints, transfer case bearings, or axle pinion bearings.

3. Component: ‘Grease nipple’ (CQ70001) – Qty 1
This (Comp 7) is a standard ‘zerk’ fitting. It is threaded into the slip-yoke assembly (Comp 6) to allow for periodic lubrication of the internal and external splines. Regular greasing is the most important maintenance step to prevent the splines from fretting, corroding, or seizing. A dry slip yoke is a common cause of Central Bridge Drive Shaft failure.

Core 3: The “High-Speed Stability” Logic (The Balancing System)

This final component group is dedicated to a single, critical purpose: high-speed rotational stability. An unbalanced Central Bridge Drive Shaft will cause destructive, harmonic vibrations throughout the entire vehicle.

1. Component: ‘Balance plate’ (2205071C6H & 2205071-A0M) – Qty As Req.
This (Comp 9 and Comp 10) are two different types of precisely weighted metal plates. The BOM lists multiple variations for each type and a quantity of ‘As Required’. This indicates the Dynamic Balancing Logic.

After the full Central Bridge Drive Shaft is assembled, it is spun on a high-speed balancing machine. Electronic sensors detect micro-imbalances. A technician then spot-welds these balance plates (Comp 9 or Comp 10) onto the shaft body (Comp 8) to counteract any heavy spots.

This precision balancing is the final step in manufacturing and is essential for a smooth, vibration-free operation. A shaft that has lost a balance weight will cause immediate and severe vibration, which can quickly destroy seals, bearings, and U-joints. This makes the Central Bridge Drive Shaft a precision-tuned component.

Central Bridge Drive Shaft: Complete 10-Part Serviceable Breakdown

The following table provides the complete, detailed breakdown of all 10 serviceable component types in the Central Bridge Drive Shaft assembly for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck. Components listed as ‘As Required’ or ‘Select’ are precision-fitting parts that must be chosen by the technician to meet build specifications.

Core Specifications

The specifications for this Central Bridge Drive Shaft are defined by its role as a high-torque, high-angle inter-axle connector. Understanding these specifications is key to ordering the correct assembly for the tandem-axle drivetrain.