Rear Axle Drive Shaft: Deconstructing 9 Critical Parts for Flawless Torque Delivery

This is a technical deconstruction of the Rear Axle Drive Shaft, a vital drivetrain component for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck. This guide details the 9 serviceable parts that ensure reliable power transmission from the gearbox to the differential, which is essential for heavy-haul operations and off-road durability.

The Rear Axle Drive Shaft is not a single part but a complex, high-speed, dynamically balanced assembly. Its primary function is to transmit the engine’s rotational power across a variable angle and distance from the gearbox to the rear axle differential. In a 6×4 dump truck like the CA3250P66K2L1T1E, this component endures immense stress, constant changes in angle due to suspension travel, and high-speed rotation. This breakdown focuses on the serviceable aspect, identifying the individual components that can be replaced during a standard rebuild or repair, which is essential for cost-effective fleet maintenance.

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

The universal joint, or U-joint, is the heart of the Rear Axle Drive Shaft assembly’s ability to articulate. This assembly allows the shaft to spin smoothly even as the rear axle moves up and down with the suspension. This specific driveshaft uses two complete U-joint assemblies, one at each end. This articulation is managed by a group of four key components working in unison.

1. Component: ‘Cross and needle roller bearing assy’ (2201030-1050) – Qty 2
This (Comp 5) is the central cross or spider. Each of its four arms, or trunnions, is a precision-ground journal designed to fit into a bearing cap. This assembly includes the four needle roller bearing caps that are pressed into the yokes. When this part fails, it typically results in significant driveline vibration or distinct audible noises during acceleration. Replacing it is a standard part of overhauling the Rear Axle Drive Shaft.

2. Component: ‘Flange yoke’ (2201023-80A) – Qty 2
This (Comp 2) is the yoke that physically bolts to the differential pinion flange and the transmission output flange. These yokes are secured by ‘Hexagon flange bolts’ (Comp 3, Qty 8) and ‘Type I non-metallic insert hex lock nuts’ (Comp 1, Qty 8).

This Fastener Logic is a critical safety system. The non-metallic insert in the nut (Comp 1) provides prevailing torque. This prevents the fasteners from backing off under the constant, high-frequency vibration inherent in a heavy-duty drivetrain. Using standard nuts and bolts without this locking feature would lead to catastrophic failure of the Rear Axle Drive Shaft.

3. Component: ‘Circlip’ (2201041-80A) – Select 8
This (Comp 4) is arguably the most critical component for U-joint longevity, functioning as a precision shim. These are the circlips, or snap rings, that lock the U-joint’s bearing caps (from Comp 5) into the yokes (Comp 2 and Comp 6).

The Bill of Materials (BOM) specifies ‘Select 8’ and lists multiple sub-part numbers (2201042-80A, 2201043-80A, etc.). This Selective Fit Logic is crucial. It means these circlips come in a range of precise thicknesses. A technician must assemble the joint and then select the correct thickness of circlip to achieve the precise, minimal end-play specified by the manufacturer. This selection process ensures there is no lateral movement, which would otherwise hammer the needle bearings to failure. This is a high-precision step in servicing the Rear Axle Drive Shaft.

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

This group of components forms the main body of the Rear Axle Drive Shaft. It is responsible for two functions: spanning the required distance between the transmission and the axle, and handling the dynamic length change required by the truck’s suspension.

1. Component: ‘Rear axle drive shaft weld yoke and spline sleeve assy’ (2201015-80A) – Qty 1
This (Comp 7) is the primary structural component. It consists of the main driveshaft tube, which is permanently welded to a yoke at one end (for one of the U-joints) and a spline sleeve (an internal spline) at the other.

This Welded Logic is a design choice for extreme strength and rigidity. The welds ensure the yokes and tube act as a single piece. This allows them to transfer immense torque without slipping, shearing, or breaking away from the tube under the extreme loads of a fully-loaded dump truck. This permanent bond is the backbone of the Rear Axle Drive Shaft.

2. Component: ‘Spline shaft yoke assy’ (2201020-80A) – 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 7).

This Plunge Logic is essential for any vehicle with a live-axle suspension. As the CA3250P66K2L1T1E’s rear axle articulates over bumps and terrain, the distance between the fixed transmission and the moving differential changes constantly. This slip-yoke assembly allows the Rear Axle Drive Shaft to lengthen and shorten dynamically, preventing the assembly from binding and destroying itself, the transmission bearings, or the differential pinion bearings.

3. Component: ‘Straight type grease nipple’ (CQ70001) – Qty 1
This (Comp 8) is a small but functionally vital part. It is a standard zerk fitting that is threaded into the slip-yoke assembly (Comp 6) to allow for periodic lubrication. Technicians must pump chassis grease into this fitting as part of a regular maintenance schedule. This grease is the only thing protecting the male and female splines (Comp 6 and Comp 7) from fretting, corrosion, and grinding themselves into dust. A dry, unlubricated slip yoke is a common cause of Rear Axle Drive Shaft clunking and eventual 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. A long, heavy rotating mass like this Rear Axle Drive Shaft will cause destructive, harmonic vibrations if it is not perfectly balanced, much like a vehicle’s tire and wheel assembly.

1. Component: ‘Balance plate’ (2201071-1H) – Qty As Req.
This (Comp 9) is a small, precisely weighted metal plate. The BOM lists multiple variations (2201072-1H, 2201073-1H, etc.) and a quantity of ‘As Required’. This indicates the Balancing Logic.

After the entire Rear Axle Drive Shaft assembly is assembled, it is placed on a high-speed dynamic balancing machine. The machine spins the shaft at operational speed and electronic sensors detect any tiny imbalance or heavy spot along its length.

The technician then spot-welds these ‘Balance plates’ (Comp 9) of a specific weight onto the driveshaft tube (Comp 7) at specific locations to counteract the heavy spots. This process is essential for a smooth, vibration-free operation at highway speeds. An unbalanced Rear Axle Drive Shaft will quickly destroy U-joints, transmission seals, and pinion bearings.

Rear Axle Drive Shaft: Complete 9-Part Serviceable Breakdown

The following table provides the complete, detailed breakdown of all 9 serviceable component types in the Rear Axle Drive Shaft assembly for the FAW Jiefang CA3250P66K2L1T1E 6×4 dump truck. Note that 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 Rear Axle Drive Shaft are defined by its role as a high-torque, high-angle driveline component for a heavy-duty dump truck application. Understanding these specifications is key to ordering the correct assembly.