Product Introduction

This is a precision-engineered split retaining ring designed to provide a secure, low-profile method of axial component retention.

• Structure & Material: Made from high-strength spring steel, it features a thin, split circular profile. The surface is coated with a durable black oxide finish for excellent corrosion resistance.

• Performance: The split design allows it to be easily installed into a groove on a shaft or housing, where it expands to lock in place and prevent axial movement of components.

• Durability: The high-tensile steel construction resists deformation and maintains its retaining force even under high vibration and temperature fluctuations.

• Compatibility: A standard metric component that fits a wide range of Sinotruk vehicle systems, ensuring reliable retention of critical parts.

Core Function

1. Axial Retention: Prevents bearings, gears, and other components from sliding off shafts or out of housings.

2. Low-Profile Design: Occupies minimal space, making it ideal for use in compact transmission and axle assemblies.

3. Easy Installation: The split design allows for quick and secure installation without special tools.

Stop Ring AZ9003990120 – SINOTRUK HW Series Gearbox Spare Part

Precision-Engineered Stop Ring AZ9003990120 for SINOTRUK HW Gearbox Performance

When your SINOTRUK HW Series gearbox demands reliable shifting and long-lasting durability, every single component matters — especially the stop ring. The Stop Ring AZ9003990120 is a critical gearbox component that prevents gear synchronizer over-travel, ensuring smooth and precise gear engagement under heavy-load conditions. Manufactured to meet OEM specifications, this stop ring delivers the exact fit and performance your fleet needs to stay on the road.

At Mettlead, we supply this genuine-quality gearbox stop ring directly from our factory in China, which means you get competitive pricing without compromising on precision or material integrity. Whether you’re maintaining a single truck or managing a fleet of SINOTRUK HOWO heavy-duty vehicles, this part is engineered to keep your transmission running smoothly mile after mile.

Key Features and Benefits of Stop Ring AZ9003990120

So, what makes this stop ring stand out from aftermarket alternatives? Let’s break down the features that matter most to procurement managers and fleet maintenance teams:

• OEM-Grade Precision: Manufactured to match the original SINOTRUK specifications, the AZ9003990120 stop ring ensures a perfect fit within the HW series gearbox assembly — no modifications required.
• Superior Material Strength: Crafted from high-grade alloy steel, this stop ring resists wear, heat deformation, and fatigue stress, even under continuous heavy-duty operation.
• Smooth Gear Synchronization: By limiting synchronizer sleeve travel, this component plays a vital role in reducing gear clash and protecting internal gearbox components from premature damage.
• Extended Service Life: Thanks to precision heat treatment and surface hardening, the stop ring maintains dimensional stability over hundreds of thousands of kilometers.
• Cost-Effective Maintenance: Factory-direct pricing from Mettlead means you can stock critical gearbox parts at a lower cost per unit, ultimately reducing your total cost of ownership.
• Fast Global Shipping: We maintain ready stock of high-demand parts like the AZ9003990120, so your order ships quickly and arrives reliably — wherever your fleet operates.

Technical Specifications – Stop Ring AZ9003990120

Below you’ll find the detailed technical parameters for this SINOTRUK HW series gearbox stop ring. These specifications help you confirm compatibility before placing your order:

Application Scenarios – Where Does the Stop Ring AZ9003990120 Fit?

Understanding exactly where this part belongs helps you make a confident purchasing decision. The Stop Ring AZ9003990120 is specifically designed for the SINOTRUK HW series manual transmission, which is widely used across China’s heavy-duty truck lineup. Here’s where you’ll typically find it:

• Compatible Gearbox Models: HW15710, HW19710, HW15712, HW19712, and other HW series variants equipped in SINOTRUK vehicles.
• Compatible Vehicle Models: SINOTRUK HOWO A7, HOWO T7H, SITRAK C7H, SITRAK C5H, and other heavy-duty trucks using the HW gearbox platform.
• Typical Application: Long-haul logistics trucks, mining dump trucks, construction vehicles, and any heavy transport application where the HW gearbox is standard equipment.

In other words, if your truck runs a SINOTRUK HW transmission, this stop ring is the part you need to maintain reliable gear synchronization throughout the gearbox’s service life.

Looking for more SINOTRUK transmission components? Browse our full range of gearbox parts or visit our dedicated SINOTRUK HOWO gearbox parts page for a complete catalog.

OEM/ODM Capability – Custom Packaging and White-Label Solutions

As a procurement manager, you likely need more than just parts — you need a supply partner who adapts to your business requirements. Mettlead offers flexible OEM and ODM services tailored to the aftermarket distribution channel:

• White-Label Packaging: We can supply the Stop Ring AZ9003990120 under your own brand packaging, helping you build brand recognition in your local market.
• Custom Packaging Design: Whether you prefer individual blister packs, bulk cartons, or branded boxes with your logo and part number, we accommodate your specifications.
• Strict Quality Control: Every batch of stop rings undergoes dimensional inspection, hardness testing, and surface quality checks before shipping — ensuring consistency across orders.
• Flexible Order Quantities: From trial orders to large container shipments, our production capacity scales to match your procurement schedule.

Explore the full lineup of SINOTRUK truck parts and spares available from our factory on our SINOTRUK HOWO truck parts brand page.

Customer Case Study – Stop Ring AZ9003990120 Bulk Order for East African Fleet

Earlier this year, a fleet maintenance company based in Kenya reached out to Mettlead with an urgent requirement. They managed over 120 SINOTRUK HOWO dump trucks operating in mining and construction, and their gearboxes were experiencing premature synchronizer wear — largely due to substandard stop rings sourced from an unreliable local supplier.

After consulting with our technical team, the client placed a bulk order for Stop Ring AZ9003990120 along with several other SINOTRUK HW series gearbox components. We shipped the entire order within 7 business days via sea freight to Mombasa port.

The results spoke for themselves: within three months of installing Mettlead’s OEM-spec stop rings, the client reported a 40% reduction in gearbox-related downtime and significantly smoother shifting performance across their fleet. They’ve since become a repeat customer, ordering gearbox stop rings and synchronizer assemblies on a quarterly basis.

“The Stop Ring AZ9003990120 from Mettlead fits perfectly — same quality as original SINOTRUK parts but at a much better price. Our drivers noticed the difference immediately.” — Fleet Maintenance Manager, Nairobi, Kenya

Frequently Asked Questions – Stop Ring AZ9003990120 SINOTRUK HW Gearbox

What is the function of Stop Ring AZ9003990120 in the HW series gearbox?

The stop ring acts as a mechanical limiter within the synchronizer assembly. It prevents the synchronizer sleeve from traveling beyond its designed range during gear engagement. Without a properly functioning stop ring, gear clash and accelerated wear on synchronizer cones can occur, potentially leading to costly gearbox overhaul.

Is the Stop Ring AZ9003990120 compatible with all SINOTRUK HW gearbox models?

Yes, the AZ9003990120 stop ring is designed for the SINOTRUK HW series gearbox family, including the HW15710, HW19710, and their variants. However, we always recommend confirming your specific gearbox model number before ordering, as some sub-variants may have different internal configurations.

What material is the Stop Ring AZ9003990120 made from?

This stop ring is manufactured from high-grade alloy steel, then heat treated and surface hardened to achieve the precise hardness and wear resistance required for heavy-duty transmission applications. The material composition matches SINOTRUK’s original equipment material standards.

How can I tell if my gearbox stop ring needs replacement?

Common symptoms of a worn or damaged stop ring include difficulty shifting into specific gears, grinding or crunching noises during gear engagement, and inconsistent synchronizer performance. During a gearbox inspection, visible scoring, cracks, or dimensional wear on the stop ring surface indicate it should be replaced immediately.

Does Mettlead supply other SINOTRUK HW gearbox parts besides the stop ring?

Absolutely. We carry a comprehensive range of SINOTRUK HW series gearbox components, including synchronizer rings, shift forks, gears, bearings, seals, and housing assemblies. You can view our complete SINOTRUK HOWO gearbox parts catalog for more details.

What is the typical lead time for Stop Ring AZ9003990120?

Since the AZ9003990120 is a high-demand item, we usually maintain ready stock. For standard orders, expect shipment within 3–5 business days. Larger bulk orders may require 7–15 days depending on quantity. We’ll always confirm lead time before you commit to the order.

Get a Competitive Quote for Stop Ring AZ9003990120 Today

Ready to secure reliable, factory-direct pricing on the Stop Ring AZ9003990120 for your SINOTRUK HW series gearbox maintenance program? Whether you need a sample order or a full container of gearbox spare parts, Mettlead is here to support your procurement goals with quality parts, transparent pricing, and dependable delivery.

Take the next step — contact us now to request a quotation, ask technical questions, or discuss custom packaging for your market. Our team typically responds within 24 hours.

Mettlead — Your trusted China-based source for SINOTRUK, HOWO, SHACMAN, FAW, WEICHAI, DONGFENG, and FOTON truck parts. Factory quality, global delivery.