Dana / Spicer DD404-370

The Dana Spicer DD404-370 is a tandem-drive axle differential designed for demanding heavy-duty truck applications. Known for its reliability, strength, and ease of service, the DD404 is ideal for fleets requiring consistent performance, high load capacity, and a low cost of ownership.

Built with hypoid gearing for quiet and efficient operation, the DD404 features a double-drive configuration—meaning both axles are powered—providing increased traction and performance in both highway and vocational settings. With a gross axle weight rating (GAWR) of 40,000 lbs, this axle is built to endure high-stress conditions including linehaul, construction, and refuse operations.

Thanks to its modular carrier design, wide gear ratio options, and compatibility with common suspension systems, the DD404 remains a popular, versatile solution for truck OEMs and aftermarket fleets alike.

Technical Specifications

General Features:

• Double-drive tandem axle for heavy-duty truck applications
• Designed for on-highway and vocational use
• Proven hypoid gear design for quiet operation and durability

Axle Rating & Load Capacity:

• Gross Axle Weight Rating (GAWR): 40,000 lbs (18,144 kg)
• Ideal for Class 8 trucks and severe-service environments

Gear Design and Ratios:

• Gear Type: Single-reduction, hypoid gearing
• Ring Gear Diameter: 15.25 inches (387 mm)
• Input Shaft Spline Count: 39-spline (standard)
• Available Gear Ratios:
  • 3.08, 3.21, 3.36, 3.55, 3.70, 3.90, 4.10, 4.33, 4.63, 4.88, 5.29

Construction and Materials:

• Carrier Housing: Cast ductile iron for strength and heat dissipation
• Heat-treated alloy steel gears for long service life
• Rugged, high-strength axle shafts for durability under high load

Lubrication and Cooling:

• Integrated pressurized lubrication system for efficient oil flow
• Optional lubrication pump available for extended service cycles
• Oil Capacity: Approx. 16–18 quarts per axle (depending on housing and configuration)

Differential Lock and Traction:

• Standard inter-axle differential (power divider) for torque distribution
• Optional driver-controlled differential lock for improved traction in off-road or slippery conditions

Suspension & Brake Compatibility:

• Compatible with multiple suspensions: air ride, leaf spring, walking beam
• ABS sensor-ready hub options available
• Multiple track widths and housing configurations available for OEM flexibility

Serviceability and Maintenance:

• Modular carrier design simplifies removal and servicing
• Commonality with Dana 404-family components reduces parts inventory needs
• Designed for long service intervals and ease of maintenance

Applications:

• Freight and linehaul trucks
• Refuse and sanitation vehicles
• Dump and construction trucks
• Logging and forestry operations
• General vocational applications

Key Benefits:

• Reliable, proven 40,000 lb GAWR performance
• Quiet and efficient hypoid gear operation
• Wide ratio range allows performance and fuel economy optimization
• Easy service and low downtime with modular carrier design
• Trusted by OEMs and fleets across North America