Conjunto do eixo central superior esquerdo da sub-caixa FAW: Uma análise abrangente de seu 4 Componentes principais

Welcome to this comprehensive technical analysis of the Conjunto do eixo central superior esquerdo da sub-caixa FAW. This is a critical set of components within the auxiliary “subcaixa” (or range box) of the transmission for the FAW Jiefang CA4251P66K24T1A3E5 6×4 trator semirreboque diesel.

O Conjunto do eixo central superior esquerdo da sub-caixa FAW é o “counter-shaft” for the transmission’s auxiliary section. Isso é “lógica” is to handle the immense torque required for the “alto” e “baixo” range split, effectively doubling the truck’s available gears. Esta montagem, which includes the shaft, rolamentos, and locating washers, is essential for the transmission’s durability.

This in-depth guide is a vital resource for professional transmission technicians and parts managers. Vamos desconstruir todo Conjunto do eixo central superior esquerdo da sub-caixa FAW em seu 4 main serviceable part numbers, explaining the critical function of the ‘Welded countershaft assembly’ (1701515FA0L), its tapered roller bearings, and its precision locating shims.

Componente principal: Welded Countershaft (1701515FA0L)

The backbone of the Conjunto do eixo central superior esquerdo da sub-caixa FAW is the ‘Welded countershaft assembly-sub box’ (1701515FA0L). The parts list specifies a quantity of two, which is a critical detail. This indicates the transmission’s auxiliary box uses a **twin-countershaft design** (ou “twin-shaft”) for its range selection.

This design splits the torque coming from the main box, sending 50% through this “Left Upper” Conjunto do eixo central superior esquerdo da sub-caixa FAW e 50% through its (identical) twin. This dramatically increases the torque-handling capacity of the gearbox, allowing for a more compact and durable design.

O termo “Welded assembly” signifies that the gears (Por exemplo, the high/low range drive gears) are permanently attached to the shaft, likely via friction welding. This creates a single, incredibly strong component that is not serviceable in individual pieces. O inteiro Conjunto do eixo central superior esquerdo da sub-caixa FAW must be replaced as a unit if a gear tooth is damaged.

The Bearing System: Tapered Roller Bearings (33109-1 & 33109-2)

Each Conjunto do eixo central superior esquerdo da sub-caixa FAW is supported at both ends by a ‘Tapered roller bearing’. The parts list breaks this down into its two serviceable components:

• ‘Outer ring-tapered roller bearing’ (33109-1) – 4 unidades
• ‘Inner ring-tapered roller bearing’ (33109-2) – 4 unidades

The quantities (4 of each) perfectly equip the two ‘Welded countershaft’ (1701515FA0L) units with a front and rear bearing set. Tapered roller bearings are essential for this application. Unlike standard ball bearings, they are designed to handle extreme loads in *two* directions simultaneously:

**1. Radial Load:** The immense separating force of the helical-cut gears pushing away from each other.

**2. Axial Load (Thrust):** O “push/pull” force that is naturally generated by the angled teeth of the helical gears. A ball bearing would be destroyed by this thrust, but a tapered bearing is designed for it. This is a critical piece of logic in the Conjunto do eixo central superior esquerdo da sub-caixa FAW.

The ‘Outer ring’ (ou “cup”) is pressed into the transmission’s rear housing. The ‘Inner ring’ (ou “cone,” which includes the rollers) is pressed onto the journal of the Conjunto do eixo central superior esquerdo da sub-caixa FAW.

Precision Logic: The Locating Washer (1701518-A0L) and Preload

The final component listed is the ‘Locating washer’ (1701518-A0L), with a quantity of two (one for each Conjunto do eixo central superior esquerdo da sub-caixa FAW). This is not a simple washer; it is a **precision shim**.

The most critical aspect of installing tapered roller bearings is setting the “preload.” This is the precise amount of “squeeze” or axial pressure applied to the bearings.

• **Too Loose:** If the preload is too loose, o Conjunto do eixo central superior esquerdo da sub-caixa FAW will have “jogo final,” allowing it to move back and forth. This causes the helical gears to misalign, leading to a loud “lamentar,” high-frequency vibration, and eventual gear-tooth failure.
• **Too Tight:** If the preload is too tight (over-shimmed), the bearings will have no running clearance. This creates immense friction and heat, which will seize, “blue,” and destroy the new bearings in a very short amount of time.

This ‘Locating washer’ é a “selective fit” shim. During a rebuild, a technician uses a dial indicator to measure the end-play and then selects a washer of the *exact* thickness required (from a set of various-thickness shims, all under this part number “family”) to achieve the perfect, factory-specified preload. This shimming process is the “lógica” no Conjunto do eixo central superior esquerdo da sub-caixa FAW and is the most important step for a successful transmission repair.

Service and Diagnostics

A failure within the Conjunto do eixo central superior esquerdo da sub-caixa FAW is a major event. The primary cause of failure is almost always lubrication-related. If the transmission oil level is low, or if the oil is contaminated with water or debris, the bearings (33109-1, 33109-2) will be the first components to fail.

The main diagnostic symptom of a failing Conjunto do eixo central superior esquerdo da sub-caixa FAW is a loud, pronounced **whining or growling noise** that is directly related to vehicle speed, not engine speed. The noise will be present in *all* gears (both high and low range) and will change pitch as the truck accelerates or decelerates. This is because this shaft is “downstream” of the main gearbox and is always spinning in relation to road speed.

A secondary symptom is the presence of a large amount of “glitter” or fine metal shavings in the sub-box’s oil during a service. This is the hardened surface of the bearing or gear (1701515FA0L) “corrosão” e “spalling” (flaking off) due to overload or lack of lubrication. Servindo o Conjunto do eixo central superior esquerdo da sub-caixa FAW requires a complete teardown of the auxiliary box, replacement of all bearings and shims, and a careful re-setting of the bearing preload using the ‘Locating washer’ (1701518-A0L).

FAW Sub-Box Left Upper Centre Shaft Assembly Parts List

A tabela a seguir fornece o completo, detalhamento de todos 4 component types identified in the ‘Sub-Box Left Upper Centre Shaft Assembly’ diagrama para o trator FAW CA4251P66K24T1A3E5. Esse Conjunto do eixo central superior esquerdo da sub-caixa FAW is a complete set for two countershafts.

Especificações Técnicas e Contexto de Montagem

As especificações para o Conjunto do eixo central superior esquerdo da sub-caixa FAW são definidos por sua função como um motor de alto torque, twin-countershaft system. O inteiro Conjunto do eixo central superior esquerdo da sub-caixa FAW set must be installed with precision preload.