Product Introduction

This is a standard single-turn spring washer designed to provide continuous tension in bolted joints, preventing fasteners from working loose under vibration.

• Structure & Material: Made from high-carbon spring steel, it features a single, split coil design. The surface is coated with a black oxide finish for corrosion resistance.

• Performance: When compressed, the washer exerts a constant spring force that maintains tension in the joint, counteracting the tendency of nuts and bolts to loosen due to engine or road vibration.

• Durability: The high-carbon steel construction resists fatigue and maintains its spring tension over long periods, ensuring reliable performance in harsh operating conditions.

• Compatibility: A standard metric component (M10 thread size) that fits a wide range of applications in the vehicle’s chassis, engine, and transmission systems.

Core Function

1. Anti-Loosening: Prevents M10 nuts and bolts from loosening under vibration, which is critical for maintaining the integrity of critical vehicle systems.

2. Tension Maintenance: Maintains a constant clamp load in bolted joints, preventing leaks in sealed connections and ensuring proper alignment of components.

3. Compensation: Compensates for minor settling or relaxation in the joint over time, ensuring consistent performance.

Spring Washer Q40310 for SINOTRUK HW Series Gearbox – OEM Quality Transmission Parts

When it comes to keeping your SINOTRUK HW series gearbox running smoothly, every small component matters — and the Spring Washer Q40310 is no exception. This precision-engineered elastic washer serves as a critical anti-loosening element inside the transmission assembly, preventing bolt fatigue and ensuring long-term fastening reliability under heavy-duty operating conditions. Whether you’re maintaining a fleet of HOWO trucks or rebuilding a gearbox on the workshop bench, this genuine-spec spring washer delivers the exact fit and performance your transmission demands.

At Mettlead, we supply factory-direct SINOTRUK gearbox components to workshops, fleet operators, and distributors across the globe. As a trusted source for SINOTRUK HOWO truck parts, we combine competitive pricing with strict quality control — so you never have to compromise between cost and reliability.

Key Features and Benefits of Spring Washer Q40310

The Spring Washer Q40310 isn’t just a simple ring of metal — it’s a carefully designed fastening solution that plays an essential role in your gearbox’s structural integrity. Here’s why technicians and procurement managers trust this component:

• Anti-Vibration Locking: The spring tension creates a continuous axial force that prevents nuts and bolts from loosening, even under constant transmission vibration and torque cycling.
• OEM-Equivalent Specification: Manufactured to match the original SINOTRUK dimensional and material standards, ensuring seamless drop-in fitment without modification.
• High-Grade Spring Steel: Made from heat-treated spring steel with surface hardening, offering excellent fatigue resistance and a long service life in demanding gearbox environments.
• Corrosion-Resistant Finish: Zinc-plated or phosphated surface treatment protects against moisture and chemical corrosion inside the transmission housing.
• Cost-Effective Maintenance: Replacing worn spring washers during routine gearbox servicing prevents costly bolt failure and unplanned downtime — a small part that saves big money.

In other words, this spring washer works quietly behind the scenes to keep your gearbox bolts tight, your transmission aligned, and your trucks on the road.

Technical Specifications – Spring Washer Q40310 SINOTRUK HW Series Gearbox

Need additional specifications or a cross-reference to confirm fitment for your specific HW gearbox model? Feel free to contact us with your VIN or gearbox nameplate details.

Application Scenarios – Where Does Spring Washer Q40310 Fit?

Understanding exactly where this component belongs helps you order with confidence. The Spring Washer Q40310 is installed in the following scenarios:

• Compatible Gearbox Models: SINOTRUK HW series manual transmissions — including HW15710, HW19710, HW15825, and HW20716 variants widely used in HOWO A7, HOWO T7H, and SITRAK C7H heavy trucks.
• Installation Positions: Gearbox housing cover bolts, shift mechanism mounting points, bearing cap fasteners, and other internal transmission bolt groups requiring anti-vibration locking.
• Service Occasions: Routine gearbox overhaul, clutch replacement, transmission rebuild, and any procedure that requires disassembly of HW gearbox fastening components.

For a complete range of transmission components — from gears and synchronizers to seals and bearings — explore our full gearbox parts category or visit our dedicated SINOTRUK HOWO gearbox parts page.

OEM/ODM Capability and Custom Packaging

As a factory-direct supplier based in China, Mettlead offers flexible manufacturing and packaging solutions designed specifically for B2B buyers:

• White-Label Packaging: We supply Spring Washer Q40310 in neutral packaging — ideal for distributors who sell under their own brand.
• Custom Branding: Need your company logo, part number label, or barcode on the packaging? We support full custom packaging design to match your brand identity.
• Strict Quality Control: Every batch undergoes dimensional inspection, hardness testing, and surface finish verification before shipment. Our QC process ensures consistent performance across every order.
• Bulk and Mixed Orders: Whether you need 1,000 pieces of Q40310 alone or want to combine it with other SINOTRUK HOWO truck parts in a consolidated shipment, we handle it seamlessly.
• Factory Visits Welcome: We encourage prospective partners to visit our facility in China to inspect production lines, review QC processes, and build long-term trust firsthand.

Customer Case Study – Spring Washer Q40310 for Fleet Maintenance in East Africa

Earlier this year, a fleet maintenance company operating over 120 HOWO dump trucks in Tanzania reached out to Mettlead for a recurring gearbox fastener issue. Their technicians had noticed increasing bolt looseness in the HW19710 gearbox housing after every 30,000 km service interval, leading to oil leaks and premature gear misalignment.

After reviewing their maintenance reports, our technical team identified that the aftermarket spring washers they had been sourcing locally did not meet the required hardness specification. We supplied a bulk order of genuine-spec Spring Washer Q40310 units — heat-treated to HRC 44–51 and zinc-plated for corrosion resistance in tropical conditions.

The result? Their gearbox re-torque intervals extended from 30,000 km to over 80,000 km, transmission oil leakage dropped significantly, and overall unplanned gearbox downtime decreased by approximately 40%. The customer has since become a repeat buyer, ordering Q40310 along with other SINOTRUK HOWO gearbox parts on a quarterly basis.

Frequently Asked Questions – Spring Washer Q40310 SINOTRUK HW Gearbox

What is the function of Spring Washer Q40310 inside the HW gearbox?

The Spring Washer Q40310 acts as an anti-loosening device. Its split-ring spring design generates a continuous elastic force between the bolt head and the mating surface, preventing rotational loosening caused by gearbox vibration, thermal cycling, and repetitive torque loads during gear shifting.

Can I reuse Spring Washer Q40310 after disassembling the gearbox?

Technically, spring washers lose a portion of their elastic recovery after compression. While a washer that still shows visible spring tension might function temporarily, best practice for heavy-duty gearbox assemblies is to replace all spring washers with new units during every reassembly. The cost is minimal compared to the risk of bolt failure.

How do I confirm that Q40310 fits my specific HW gearbox model?

Q40310 is a standardized fastener part number used across multiple SINOTRUK HW gearbox variants. To confirm fitment, check your gearbox nameplate for the assembly model number (e.g., HW19710) or consult the SINOTRUK parts catalog. Alternatively, send us your VIN or gearbox serial number and our team will verify compatibility for you.

What material is the Spring Washer Q40310 made from?

This spring washer is manufactured from 65Mn spring steel — a medium-carbon manganese steel known for excellent elasticity and fatigue resistance. After heat treatment, it achieves a hardness range of HRC 44–51, which is the standard specification for automotive-grade spring washers under GB/T 93.

Is there a minimum order quantity for Spring Washer Q40310?

Mettlead offers flexible MOQs to accommodate both small workshop orders and large distributor requirements. Since spring washers are lightweight and compact, we can efficiently ship large quantities at low freight cost. Contact us for a quote tailored to your volume needs.

Can you supply other gearbox fasteners alongside Q40310?

Absolutely. We stock a comprehensive range of SINOTRUK HW gearbox fasteners — including flat washers, hex bolts, lock nuts, and copper sealing washers. Consolidating these items in a single order from our gearbox parts catalog helps reduce your shipping costs and simplify procurement.

Ready to Order Spring Washer Q40310? Get a Fast Quote Today

Don’t let a worn-out spring washer put your gearbox — and your fleet — at risk. Whether you need a small batch for urgent repairs or a bulk supply for ongoing maintenance programs, Mettlead is ready to deliver genuine-quality Spring Washer Q40310 for SINOTRUK HW Series Gearbox straight from the factory to your door.

• ✅ Factory-direct pricing — no middleman markup
• ✅ Strict quality control on every batch
• ✅ Fast, reliable global shipping
• ✅ Flexible payment terms with secure transactions
• ✅ Custom packaging and white-label options

Contact us now to request pricing, confirm part fitment, or discuss your bulk order requirements. Our technical sales team typically responds within 12 hours — and we’re always happy to help you find the right parts for your SINOTRUK gearbox.