Meritor MD2014X-643

The Meritor MD2014X-643 is a heavy-duty tandem rear-drive axle differential engineered to deliver exceptional low-speed torque and pulling power in the most demanding on- and off-road conditions. Featuring an aggressive 6.43:1 gear ratio, this differential is purpose-built for Class 8 trucks operating in severe-service environments such as logging, construction, refuse hauling, and mining, where durability and power take priority over speed.

As part of Meritor’s proven MD2014X series, the MD2014X-643 utilizes rugged hypoid gearing and a modular, top-load carrier design that allows for ease of service and long-term reliability. This high-ratio model is ideal for vocational fleets that require consistent performance, high payload capacity, and long service intervals under extreme stress and terrain.

Key Features

• Model: MD2014X-643
• Series: Meritor MD2014X – Tandem Rear Drive Axle Series
• Axle Capacity: 40,000 lbs (20,000 lbs per axle)
• Gear Ratio: 6.43:1
• Differential Type: Standard open (non-locking)
• Gear Type: Hypoid gears for superior torque transfer and durability
• Carrier Assembly: Modular top-load design for easy access and maintenance

Applications & Benefits

• High-Torque Gear Ratio: 6.43:1 ratio ensures superior torque for demanding grades, heavy loads, and rugged terrain
• Designed for Extreme Conditions: Ideal for construction trucks, log haulers, refuse vehicles, and other off-road or low-speed duty cycles
• Long-Term Reliability: Built to handle extreme torque loads with minimal maintenance
• Serviceable Design: Modular carrier allows for easier rebuilds and faster downtime recovery
• OEM-Quality Fit: Designed to match factory specs for seamless integration into existing drivetrain systems

At General Truck Parts, we offer both new and remanufactured Meritor MD2014X-643 differentials, rebuilt to OEM specifications and tested for quality and durability. Our reman units undergo a full inspection, component replacement, and dynamic testing to ensure performance you can trust.

Need help determining if this ratio is right for your truck? Our experts can assist with VIN lookups, gear ratio matching, and fitment verification. Request a Quote or call today to check availability, pricing, and shipping options.

Technical Specifications:

• Axle Model: MD2014X-643
• Configuration: Tandem rear-drive axle
• Gross Axle Weight Rating (GAWR): 40,000 lbs
• Gear Ratio: 6.43:1
• Differential Type: Open (non-locking)
• Input Spline Count: Typically 39 or 41 splines (verify per vehicle application)
• Lubrication: Oil-lubricated system (SAE 85W-140 gear oil recommended)
• Brake Compatibility: Compatible with 16.5″ S-cam drum brakes and air disc brakes
• Suspension Compatibility: Designed for use with air ride, multi-leaf, and vocational suspension systems
• OEM Applications: Common in Freightliner, Kenworth, Mack, Peterbilt, International, Volvo, and other Class 8 platforms