Genuine Sinotruk Washer (Turbine Box) 805-338-365 – Precision Load Distribution & Unmatched Durability for Howo Drivetrain Systems

Engineering Excellence Behind the 805-338-365 Turbine Box Washer

The 805-338-365 is far more than a simple flat washer – it is a precision-engineered component designed to withstand the high rotational speeds, torque spikes, and thermal cycling typical of turbine box and transmission applications. Manufactured from a premium high-carbon steel alloy (SAE 1074/1095), it is carefully heat-treated to achieve a hardness of 38–42 HRC, providing exceptional resistance to deformation and embedment under high clamp loads. Its flatness and parallelism are held to within 0.05 mm, ensuring uniform load distribution across the entire bearing surface.

The zinc-nickel coating on the 805-338-365 offers outstanding protection against corrosion, far surpassing standard zinc plating. This is especially critical for drivetrain components that are often exposed to road spray, salt, and high temperatures. The coating also provides a consistent friction coefficient, which helps in achieving accurate torque-tension relationships during assembly – a key factor in preventing both under-tightening and over-tightening in critical turbine box joints.

In typical turbine box applications, the 805-338-365 is used under high-strength bolts (M16) that secure the turbine housing, bearing caps, or oil pump covers. Its 16mm inner diameter fits M16 bolts perfectly, and its 30mm outer diameter offers a large bearing area, preventing the bolt head or nut from embedding into the relatively soft aluminium or cast iron housing. This reduces the risk of joint loosening and extends the service life of both the fastener and the turbine box assembly.

Technical Specifications – Washer (Turbine Box) 805-338-365

Parameter	Specification
OEM Part Number	805-338-365
Product Name	Washer (Turbine Box) – Heavy-duty flat washer
Brand	Sinotruk (Genuine OEM)
Inner Diameter (ID)	16.5 mm (nominal for M16)
Outer Diameter (OD)	30.0 mm
Thickness	3.0 mm
Material	High-carbon spring steel (SAE 1074/1095)
Hardness	38 – 42 HRC
Coating	Zinc-nickel (yellow passivation)
Corrosion Resistance	≥ 720 hours salt spray (ISO 9227)
Flatness Tolerance	≤ 0.05 mm
Application	Turbine box, torque converter, transmission housings, bearing caps
Compatible Models	Howo A7, T7, C7H, HW series; Sinotruk heavy-duty trucks

Why the Genuine Sinotruk 805-338-365 Outperforms Generic Washers

Generic washers are often made from low-grade steel that is not heat-treated, leading to rapid deformation under the high clamp loads typical of turbine box joints. The 805-338-365, with its hardened spring steel construction and zinc-nickel coating, maintains its flatness and thickness even after years of service, ensuring consistent load distribution and preventing joint loosening. Its larger outer diameter (30mm) provides a significantly larger bearing area than generic washers, reducing the risk of embedment into the turbine box housing.

Moreover, the precise dimensions of the 805-338-365 guarantee that it will not interfere with the bolt threads or the bearing surface of the component being clamped. Generic washers often have oversized IDs or undersized ODs, which can lead to improper seating and uneven loading, increasing the risk of bolt loosening or component damage – a dangerous situation in high-speed drivetrain applications.

Advanced Material Science for Thermal Stability

The high-carbon steel used in the 805-338-365 is specifically selected for its ability to maintain hardness and dimensional stability under the high temperatures encountered in turbine box environments. Its fine-grained microstructure, achieved through controlled quenching and tempering, provides excellent resistance to creep and stress relaxation, ensuring that the washer continues to perform its load-spreading function even after thousands of thermal cycles.

Compatibility and Fitment

The 805-338-365 is a direct replacement for the original turbine box washer in a wide range of Sinotruk and Howo models. Its dimensions are optimized for M16 bolts, with a 16.5mm ID that accommodates the nominal bolt diameter and a 30mm OD that fits standard heavy-duty flanged nuts and bolt heads. Always verify that the washer thickness (3.0mm) does not adversely affect thread engagement or clamp length in your specific application.

Explore the full range of genuine Howo Parts available for your fleet, including drivetrain components, fasteners, and transmission hardware. The 805-338-365 washer is an essential part of that ecosystem – and with Sinotruk’s original quality, you can be confident that every critical joint will be properly supported.

Installation Best Practices for the 805-338-365

Proper installation of the 805-338-365 is critical to ensure the safety and performance of your turbine box assembly. Always place the washer directly under the bolt head or nut, with the smooth (or coated) side facing the bearing surface to minimise friction and galling. Ensure that the washer sits flat against the joint surface and that the bolt or nut can rotate freely without binding. Apply the recommended torque for the specific bolt size and grade (typically 280–320 Nm for M16 bolts), and re-torque after the initial run-in period to account for any settlement.

During routine maintenance, inspect the 805-338-365 for signs of deformation, corrosion, or cracking. If any washer shows signs of embedding or distortion, it should be replaced with a new 805-338-365 to maintain proper clamp force and load distribution.

Built for Nigeria – Durable Load Support in Harsh Environments

Nigeria’s heavy-duty trucking sector demands components that can withstand extreme heat, high humidity, dust, and constant vibration. The 805-338-365 is engineered to excel in these conditions. Its hardened steel construction and zinc-nickel coating ensure that it resists both mechanical deformation and corrosion, maintaining its effectiveness over the long term.

Furthermore, the precise load distribution provided by the 805-338-365 helps prevent fretting and galling between bolt heads and the turbine box housing – a common issue that can lead to costly repairs and downtime. By choosing the genuine Sinotruk 805-338-365, fleet operators can reduce maintenance frequency and extend the service life of their vehicles’ critical drivetrain components.

Protect Your Turbine Box with the Genuine 805-338-365 Washer

The 805-338-365 Washer (Turbine Box) is a small but vital component that ensures the integrity and reliability of your vehicle’s drivetrain. Its superior material, precise dimensions, and exceptional corrosion resistance make it the definitive choice for professional workshops and fleet managers. Every time you install a genuine Sinotruk 805-338-365, you are ensuring that your turbine box connections remain secure, reducing the risk of loosening and failure.

Don’t settle for generic washers that may not provide the same level of protection and durability. Insist on the genuine 805-338-365 – the washer trusted by experienced mechanics and fleet operators across Nigeria. With its proven performance in heavy-duty applications, this washer delivers the reliability and peace of mind you deserve.

Genuine Sinotruk 805-338-365 – Engineered for excellence. Built for Africa. Trusted by professionals.

Packaging & Shipping

Every Howo part is carefully packaged and shipped to ensure it arrives in perfect condition, ready for installation. Our professional logistics process guarantees timely delivery across Nigeria.

Secure Packaging

Each Howo part is individually wrapped in protective materials and placed in reinforced cardboard boxes to prevent damage during transit.

Dedicated Transport

We use our own Sinotruk logistics fleet for reliable delivery, ensuring parts reach customers quickly and safely across all regions of Nigeria.

Quality Inspection

Before shipping, each part undergoes final quality checks and is clearly labeled with its OEM number for easy identification.

Nationwide Distribution

Our extensive distribution network covers all major cities and rural areas in Nigeria, ensuring prompt delivery to construction sites, workshops, and businesses.

Shipping Information for Nigerian Customers

• Standard Delivery: 3-5 business days to major cities (Lagos, Abuja, Port Harcourt, Kano)

• Express Delivery: 1-2 business days available for urgent orders

• Regional Coverage: We deliver to all 36 states including remote areas

• Tracking: All shipments include real-time tracking information

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