Product Introduction

• Structure: Precision closed-die forging from 20CrMnTi alloy steel, with an external involute tooth profile (32 teeth) and internal splines (16 teeth) for sliding engagement with the main shaft. The gear features a flat friction face (no integrated cone) designed to pair with a separate synchronizer ring. The entire gear undergoes full carburizing, quenching, and precision grinding, achieving surface hardness HRC 58–62(anti-pitting/wear) and core hardness HRC 33–45 (anti-impact fracture). The tooth surface roughness is Ra ≤ 0.8 μm for smooth meshing.

• Performance: The carburized tooth surface resists pitting and wear during long-term medium-speed cruising, with a service life exceeding 50,000 hours. The precision-ground tooth profile ensures smooth meshing with the countershaft 4th gear, reducing operating noise by approximately 12% compared to standard gears. The internal splines maintain a stable sliding fit with the main shaft, preventing gear slippage under medium loads.

Core Function

1. 4th gear power transmission: Transmits torque from the main shaft to the countershaft 4th gear, providing a medium torque ratio for steady-speed cruising of 30t-rated vehicles.

2. Synchronizer cooperation: The flat friction face works with the 4th/5th gear synchronizer ring to equalize speeds, enabling smooth shifting under medium load.

3. Stable sliding engagement: The internal splines ensure consistent alignment with the main shaft, preventing radial runout and meshing noise.

Main Shaft 4th Gear AZ2210040224 – SINOTRUK HW Series Gearbox Replacement Part

When your SINOTRUK HW series gearbox demands a reliable 4th gear replacement, the Main Shaft 4th Gear AZ2210040224 delivers the precision-engineered performance your fleet depends on. Designed to meet OEM specifications, this gearbox gear ensures smooth power transmission, reduced drivetrain noise, and extended service life — even under the most demanding heavy-duty conditions. At Mettlead, we supply this critical transmission component directly from our factory, which means you get genuine quality at a competitive price, without the middleman markup.

Key Features and Benefits of Main Shaft 4th Gear AZ2210040224

Choosing the right gearbox component isn’t just about fit — it’s about long-term reliability and total cost of ownership. Here’s why procurement managers across Africa, the Middle East, and Southeast Asia trust this particular gear:

• OEM-Grade Precision: Manufactured to match the original SINOTRUK HW series gearbox specifications, the AZ2210040224 main shaft 4th gear guarantees seamless integration without modification.
• Superior Material Composition: Forged from high-strength alloy steel, this gear undergoes carburizing and hardening treatments that significantly improve wear resistance and fatigue strength.
• Optimized Tooth Profile: The carefully ground gear teeth reduce meshing noise and vibration, resulting in smoother gear shifts and less stress on adjacent drivetrain components.
• Extended Service Life: Thanks to strict heat treatment processes, this 4th gear maintains dimensional stability under high torque loads, which translates to fewer unplanned maintenance stops for your fleet.
• Factory-Direct Cost Savings: By sourcing directly from Mettlead, you eliminate distributor markups and enjoy transparent, competitive pricing on every order.

Technical Specifications – Main Shaft 4th Gear AZ2210040224

Accurate specifications matter when you’re matching parts to your exact gearbox model. The following table outlines the key parameters for this SINOTRUK HW series main shaft 4th gear:

Application Scenarios – Where Does AZ2210040224 Fit?

The Main Shaft 4th Gear AZ2210040224 is specifically designed for the SINOTRUK HW series gearbox, which is widely used across multiple heavy-duty truck platforms. If you’re managing a mixed fleet or sourcing parts for resale, here’s where this gear fits perfectly:

• SINOTRUK HOWO A7 Heavy-Duty Trucks equipped with HW19710 or HW19712 transmissions
• SINOTRUK SITRAK C7H / T7H Series running HW series manual gearboxes
• SINOTRUK HOWO T5G / T7H Tractors used in long-haul logistics operations
• Mining and Construction Dump Trucks that rely on SINOTRUK HW gearbox platforms for high-torque applications

In other words, whether your vehicles haul cargo across highways or work in rugged off-road environments, this 4th gear transmission component keeps the power flowing smoothly from engine to wheels. For more compatible gearbox parts and SINOTRUK HOWO gearbox components, browse our full catalogue.

OEM/ODM Capability and Custom Packaging

We understand that every market has different requirements. That’s exactly why Mettlead offers flexible solutions for importers, wholesalers, and fleet operators worldwide:

• White-Label Packaging: Want to sell under your own brand? We provide neutral or custom-branded packaging for the Main Shaft 4th Gear AZ2210040224 and all our SINOTRUK HOWO truck parts.
• Strict Quality Control: Every gear passes through multiple inspection stages — dimensional verification, hardness testing, and surface finish checks — before it leaves our warehouse.
• Flexible Order Quantities: Whether you need a single replacement unit or a container load for your warehouse, we accommodate orders of all sizes.
• Factory Visits Welcome: We encourage procurement teams to visit our facilities in China to inspect production processes and build long-term partnership confidence.

Customer Case Study – Main Shaft 4th Gear AZ2210040224 in Action

Earlier this year, a fleet management company based in Nigeria reached out to us with an urgent problem. They operated over 40 SINOTRUK HOWO trucks on interstate haulage routes, and several units were experiencing premature 4th gear failure in their HW series gearboxes. The root cause? They had previously sourced low-quality aftermarket gears that couldn’t withstand the constant high-torque loads of fully loaded trailers.

After switching to Mettlead’s Main Shaft 4th Gear AZ2210040224, the results spoke for themselves. Within six months, not a single replacement gear showed signs of abnormal wear. The client reported smoother gear engagement, significantly reduced downtime, and an estimated 30% savings on transmission maintenance costs compared to their previous supplier. Today, they order all their SINOTRUK HW series gearbox parts exclusively through Mettlead — including countershaft gears, synchronizer assemblies, and output flanges.

This case reinforces a simple truth: when you invest in OEM-equivalent quality for critical components like the AZ2210040224 main shaft 4th gear, you protect your fleet — and your bottom line.

Frequently Asked Questions – Main Shaft 4th Gear AZ2210040224

What gearbox models does the Main Shaft 4th Gear AZ2210040224 fit?

This gear is designed for the SINOTRUK HW series gearbox family, including the HW19710, HW15710, HW19712, and related variants. It serves as a direct replacement for the original OEM 4th gear on the main shaft assembly.

How can I verify that AZ2210040224 is the correct part number for my truck?

The most reliable method is to check the nameplate on your existing gearbox housing or refer to your truck’s original parts catalogue. If you’re unsure, simply send us your gearbox model number and VIN, and our technical team will confirm compatibility within 24 hours.

What material is used, and how does it affect durability?

The AZ2210040224 main shaft 4th gear is manufactured from high-strength alloy steel that undergoes carburizing, quenching, and precision grinding. This process produces a tooth surface hardness of HRC 58–62, which dramatically improves resistance to pitting, spalling, and fatigue cracking under sustained load.

Is this gear suitable for heavy-load or mining truck applications?

Absolutely. The heat treatment and material grade of this gear are specifically chosen to handle high-torque environments. Many of our customers use it in mining dump trucks and overloaded haulage vehicles without any issues.

Can I order a single piece, or is there a minimum order requirement?

Our MOQ for the Main Shaft 4th Gear AZ2210040224 is just one piece, making it easy for you to order emergency replacements. Of course, bulk orders attract better unit pricing and priority shipping arrangements.

How should I store this gear before installation?

Keep the gear in its original protective packaging, stored in a cool, dry environment away from direct moisture or corrosive chemicals. The anti-rust oil coating applied at our factory protects the gear surfaces during storage for up to 12 months under normal warehouse conditions.

Ready to Source Your Main Shaft 4th Gear AZ2210040224?

Stop letting gearbox failures eat into your fleet’s productivity. Whether you need a single replacement or a bulk supply of SINOTRUK HW series transmission parts, Mettlead is ready to deliver — fast, affordable, and quality-guaranteed.

Get your competitive quote today. Send us your part number, required quantity, and destination, and our team will respond with pricing and lead time within 12 hours. Contact us now to start your order or ask any technical questions about the AZ2210040224 main shaft 4th gear.

Mettlead — Your Factory-Direct Partner for SINOTRUK, HOWO, SHACMAN, FAW, WEICHAI, DONGFENG, and FOTON Truck Parts Worldwide.