FAW Transmission Control Logic Assembly: A Comprehensive Focus on 50 Serviceable Components

Welcome to this comprehensive technical guide on the FAW Transmission Control Logic Assembly (without PTO). This is the complete, multi-part driver interface and linkage system for the manual transmission in the FAW Jiefang CA4251P66K24T1A3E5 6×4 diesel semi-trailer tractor.

The FAW Transmission Control Logic Assembly is the entire “shifter” system, responsible for translating the driver’s hand movements into precise, mechanical gear selection inside the gearbox. It includes the in-cab ‘Transmission control handle’ (1703025A91W-C00), the ‘Transmission control rod’ (1703021A61B), and the extensive network of linkages, скобки, and pneumatic pipes that connect the cab to the transmission.

This in-depth guide is a critical resource for professional technicians and fleet managers. We will deconstruct the entire FAW Transmission Control Logic Assembly into its 50 serviceable components, detailing the function of the in-cab shifter, the critical floor seal, the vibration-damping “soft pad” system, the pneumatic range-shifter pipes, and the final mechanical linkages.

The Driver Interface: Shifter Handle and Ball Joint

The FAW Transmission Control Logic Assembly begins inside the cab. The ‘Transmission control handle & gear plate assy’ (1703025A91W-C00) is the component the driver holds. This assembly includes the gear knob (with the shift pattern) and the upper rod, или “stick.”

This stick pivots on a ‘Ball pin-transmission control rod’ (1703013C70A). This precision-machined ball joint is the heart of the shifter’s “feel.” It is housed within a ‘Bushing’ (1703011C70A) and ‘Rear gasket’ (1703012C70A) to provide a smooth, low-friction pivot point.

This entire joint is protected from cab-side dust and spills by the ‘Ball pin cover’ (1703016C70A) and the ‘Sealing cover-transmission control rod’ (1703018C70A), which is held in place by a ‘Clamping spring’ (1703019C70A). This sealed, precise joint is the first stage in the FAW Transmission Control Logic Assembly, translating the driver’s “H-pattern” movements into precise fore-aft and side-to-side motion.

Cab Sealing: The Floor Seal and Dust Cover System

A critical part of the FAW Transmission Control Logic Assembly is the “cab-floor interface.” This is a complex seal designed to completely isolate the driver’s cab from the noise, fumes, heat, and road grime of the chassis below.

This system is centered on the ‘Sealing seat assy-cab floor’ (1703030-61Б). This is a large, molded rubber boot or “seat” that creates the main seal against the cab’s floor pan. It is secured by a ‘Buckle-sealing seat assy’ (1703036А70А).

Этот “seat” protects a dual-layer ‘Dust cover’ system. The ‘Upper dust cover’ (1703041-61Б) and ‘Lower dust cover’ (1703046-61Б) form a “bellows” that can flex as the shifter moves. These are held in place by the ‘Upper support plate’ (1703061А70А), ‘Lower support plate’ (1703060-61С), and their respective ‘Buckles’ (1703043А70А, 1703048А70А). A tear in this boot system is a major issue, leading to a loud, hot, and fume-filled cab. This sealing system is a vital, non-mechanical part of the FAW Transmission Control Logic Assembly.

Vibration Isolation: The “Soft Pad” Damping System

The transmission and engine vibrate intensely, while the cab is “air-ride” или “rubber-mounted” to be still. The FAW Transmission Control Logic Assembly must bridge this gap without transferring the vibration to the driver’s hand. This is achieved with a sophisticated “soft pad” damping system.

The parts list calls for eight ‘Soft pad seat’ (1703076А70А), eight ‘Soft pad’ (1703077А70А), and eight ‘Gasket’ (1703079А70А) единицы. These components create eight complete rubber “shock absorbers.” They are used to mount the ‘Transmission control rod bracket’ (1703071-91Вт) to the chassis.

The ‘Sleeve-transmission control rod upper bracket’ (1703078-74А) units act as steel cores for these mounts. This entire sub-assembly “floats” the shifter bracket on these 8 rubber pads, completely isolating the ‘Transmission control rod’ (1703021A61B) from high-frequency “buzzing.” The ‘Soft pad assy-transmission control rod’ (1703085-61Б) provides further damping, обеспечение FAW Transmission Control Logic Assembly feels solid and comfortable, not like a vibrating piece of machinery.

Pneumatic Logic: The Range/Splitter Control Piping

Этот FAW Transmission Control Logic Assembly controls a 12-speed (or more) transmission, which requires a “range” или “splitter” selection. This is not done mechanically, but pneumatically (with air). The ‘Transmission control pipe bundle assy’ (1703330-99А) is a set of pre-bent, color-coded air lines.

When the driver flips the range-selector switch on the gear knob, it sends an electrical signal to a solenoid valve block (see assembly 155). That block then sends high-pressure air through this ‘Pipe bundle’ to the ‘FAW Auxiliary Cylinder Assembly’ (see assembly 168), which physically shifts the sub-box.

The ‘Intake pipe assy-transmission’ (1703640-52Вт) and ‘Terminal-type pipe joint assy’ (1703610-1500) are the main “supply” lines that feed compressed air into this control system. A leak in any of these air lines is a critical failure of the FAW Transmission Control Logic Assembly, as it will leave the driver unable to select half of their gears (НАПРИМЕР., stuck in “Low Range”).

The Mechanical Linkage: Rods, Arms, and Brackets

The final part of the FAW Transmission Control Logic Assembly is the set of heavy-duty rods that create the final mechanical connection. The ‘Transmission control longitudinal rod with connector assy’ (1703095-91Вт) is the main “push-pull” rod that connects the in-cab shifter to the transmission.

This rod actuates the ‘Rear joint assy-transmission control arm’ (1703145А70А), which is the lever that physically enters the transmission’s “верхняя крышка” (see assembly 153). This connection is made via the ‘Fixed arm connecting rod & joint assy’ (1703110-56А).

These rods are held in place and guided by various brackets, including the ‘Main wiring harness bracket’ (3724426-68В), which doubles as a support. The bushings (‘Sleeve’ 1703081A92W, 1703082-61Б, 1703083-61Б) are critical, as they prevent “slop” или “play” in the linkage, ensuring a precise and confident gear shift. The entire FAW Transmission Control Logic Assembly is a precision system from start to finish.

FAW Transmission Control Logic Assembly Parts List (1/2)

The following table provides the first 25 components for the FAW Transmission Control Logic Assembly diagram for the FAW CA4251P66K24T1A3E5 tractor.

FAW Transmission Control Logic Assembly Parts List (2/2)

This table details the remaining components for the FAW Transmission Control Logic Assembly, focusing on the external linkages and pneumatic controls.

Technical Specifications and Assembly Context

The specifications for the FAW Transmission Control Logic Assembly are defined by its complex function as a vibration-damped, pneumatically-assisted, mechanical shift linkage. The FAW Transmission Control Logic Assembly connects the cab to the gearbox.