The WG221004000010 5th Gear (Overdrive Gear) is a core transmission component in heavy-duty truck gearboxes, specially designed for high-speed cruising conditions.
It enables overdrive operation, allowing the vehicle to run at higher speed while reducing engine RPM, improving fuel efficiency and reducing engine wear. It is widely used in long-distance logistics trucks operating under continuous high-speed driving conditions.

Core Function
- Enables 5th gear overdrive transmission
- Reduces engine RPM during highway cruising
- Improves fuel economy and reduces fuel consumption
- Ensures smooth high-speed torque delivery
- Maintains stable and efficient transmission performance
Product Advantages
● Overdrive Gear Ratio Design
This gear adopts a high-speed overdrive ratio, where output speed is higher than input speed.
Benefits:
- Lower engine RPM at cruising speed
- Reduced fuel consumption
- Less engine wear and heat generation
- Ideal for long-distance highway transport
● High-Strength 20CrMnTi Alloy Steel
Made from 20CrMnTi low-carbon alloy structural steel, featuring:
- Fine and dense forged structure
- Excellent toughness and impact resistance
- Strong load-bearing capacity under high torque
After heat treatment:
- Deep carburizing + quenching
- High surface hardness with tough core
- Excellent fatigue resistance and anti-breakage performance
● Precision Hardened Gear Teeth
Gear teeth are processed through:
- Deep carburizing and quenching
- CNC precision grinding
Performance advantages:
- High wear resistance and anti-pitting capability
- Stable tooth profile under long-term high-speed operation
- Reduced gear noise and vibration
- No abnormal noise or whine at high speed
● Smooth Meshing & Low Noise Operation
Precision ground tooth surfaces ensure:
- Smooth gear engagement
- Low transmission impact
- Stable high-speed operation
- Reduced vibration and gearbox noise
This significantly improves driving comfort and transmission durability.
● High-Precision Spline Connection
The internal spline is processed by precision broaching:
- Uniform clearance with input shaft
- Strong torque transmission without slippage
- No looseness or power loss under load
Ensures efficient and stable power delivery.
● Oil Bath Lubrication Optimization
Designed for gearbox oil environment:
- Fully lubricated gear teeth and root area
- Fast heat dissipation
- Prevents overheating and surface pitting
- Stable operation during long-distance high-speed driving
Technical Features
- Material: 20CrMnTi alloy structural steel
- Heat treatment: Carburizing + quenching + tempering
- Tooth surface: Hardened & precision ground
- Gear type: Overdrive (high-speed gear ratio)
- Machining: CNC grinding + spline broaching
- Surface treatment: Anti-rust coating (oil-resistant)
- Designed for oil bath lubrication system
Application Scope
- Heavy-duty truck main transmission systems
- Highway long-distance logistics trucks
- Tractor units and freight carriers
- High-speed cruising applications
- OEM gearbox assembly and repair
Performance Benefits
- Lower engine RPM at high speed
- Significant fuel savings
- Smooth and quiet transmission
- High load resistance without gear failure
- Reduced maintenance and longer service life
Supply & Service
- Ready stock available for fast delivery
- OEM customization supported
- Stable supply for long-term cooperation
- Technical support for installation and selection



