Main Shaft Composite Member for HOWO A7 8X4

The Main Axle block is a large retaining plate that secures the main shaft assembly within the transmission housing. It provides axial stopping and prevents end float of the shaft.

Manufactured from hardened steel with a precise flat surface, the Main Axle block ensures even load distribution across the thrust face and resists deformation under high axial loads.

Proper installation of the Main Axle block with the correct torque is critical to maintain the main shaft’s position and prevent gear disengagement.

The Reverse gear is a dedicated gear that meshes with the countershaft reverse gear to provide backward motion. It is designed with straight-cut teeth for strength and durability.

This gear is case-hardened and ground to achieve a smooth tooth profile, reducing noise during reverse operation. Its robust construction withstands the shock loads often encountered when manoeuvring.

Inspection of the Reverse gear for chipped or worn teeth is important, as damaged teeth can cause difficult engagement and excessive noise.

The Clamp is a spring-like retaining ring that holds components such as synchroniser hubs or gears in position on the main shaft. It applies a constant radial force to prevent axial movement.

Made from high-carbon spring steel, the Clamp maintains its elasticity over many cycles of expansion and contraction, ensuring reliable retention.

When replacing the Clamp, it is important to use the correct size to avoid excessive clearance or binding.

The Spline block plate is a thin metal disc that acts as a spacer and thrust washer between splined components on the main shaft. It prevents direct metal-to-metal contact and reduces wear.

This plate is precision-stamped from wear-resistant steel and surface-treated to reduce friction. Its thickness is carefully controlled to achieve the required end play.

Multiple Spline block plates may be stacked to fine-tune axial clearance during assembly.

The Main axle sleeve is a tubular component that slides over the main shaft and provides a bearing surface for gears to rotate freely. It also acts as a spacer between adjacent gears.

Manufactured from case-hardened steel with a ground internal bore, the Main axle sleeve ensures low friction and long wear life. Its outer diameter is machined to accept gear bores with appropriate clearance.

Regular inspection of the Main axle sleeve for scoring or galling is recommended, as these can indicate lubrication problems or misalignment.

The Spline adjust plate is a thin shim used to adjust the axial positioning of splined gears on the main shaft. It compensates for manufacturing tolerances and wear.

These plates are available in various thicknesses and are stacked to achieve the correct end float. They are made from hardened steel with a smooth finish.

Correct selection of Spline adjust plates is essential for proper gear alignment and synchroniser operation.

The First stage gear is the lowest gear ratio on the main shaft, providing maximum torque for starting and climbing. It is the largest diameter gear with the most teeth.

This gear is subjected to the highest stresses and is therefore made from premium alloy steel with deep case hardening. Its tooth profile is optimised for high load capacity.

Regular oil changes help maintain the First stage gear by flushing away wear debris and ensuring adequate lubrication.

The Second stage gear provides a medium-low ratio for moderate loads and acceleration. It is smaller than the first gear but larger than the higher gears.

This gear is precision hobbed and shaved to achieve a quiet and efficient engagement. Its surface hardness ensures resistance to pitting and scoring.

When replacing the Second stage gear, it is advisable to also check the mating countershaft gear for wear.

The Main shaft adjust shim is a precision-ground washer used to set the correct end play of the main shaft assembly. It is available in multiple thicknesses to suit different clearance requirements.

Specific thicknesses include 6.15mm, 6.30mm, 6.45mm, 6.60mm, 6.75mm, 6.90mm, and 7.05mm. Each shim is clearly marked for easy identification.

Choosing the correct Main shaft adjust shim is critical to prevent excessive axial movement, which can lead to gear disengagement and bearing damage.

The Main axle with ball joint integrates a spherical bearing at one end to accommodate angular misalignment between the main shaft and the output shaft or clutch.

This assembly includes a hardened ball stud and a precision-machined socket that provides smooth articulation while transmitting torque. It is lubricated via the transmission oil.

Inspection of the ball joint for wear or play is essential, as excessive clearance can cause vibration and noise.

The Hex keyt is a hexagonal-shaped key used to lock a gear or sleeve to the main shaft, preventing relative rotation. It fits into a keyway and a matching slot.

Manufactured from hardened tool steel, the Hex keyt provides a positive drive and can be easily removed during disassembly. Its hexagonal shape allows for even load distribution.

When installing the Hex keyt, ensure it is fully seated to prevent shearing under torque.

The Pin is a cylindrical dowel used for precise alignment of mating components such as housings or covers. It ensures repeatable positioning during assembly.

Made from ground steel with a tight tolerance, the Pin is press-fitted into one part and slides into a mating hole in the adjacent component.

Replacing damaged or worn Pins is important to maintain accurate alignment and prevent premature wear of bearings and gears.

The Third stage gear provides a medium-high ratio for cruising speeds. It is designed for reduced noise and smooth power transfer at highway speeds.

This gear features helical teeth that offer quieter operation and better load distribution compared to straight-cut gears. It is manufactured with a high-quality finish.

Monitoring the Third stage gear for pitting or spalling is recommended, as these signs can indicate fatigue or lubrication breakdown.

The Four stage gear is the highest forward gear, providing an overdrive ratio for fuel efficiency at high speeds. It is the smallest gear on the main shaft.

This gear is lightweight and optimised for minimal friction. Its teeth are specially treated to reduce wear under sustained high-speed operation.

When servicing the Four stage gear, also check the corresponding countershaft gear and bearings for even wear.