Traxxas Front Extreme Heavy Duty Driveshaft Assembly 6851A

The Traxxas 6851A is a complete front Extreme Heavy Duty driveshaft assembly designed as a replacement or durability upgrade for compatible Traxxas 4X4 vehicles.

Its reinforced composite U-joint construction adds material around critical high-stress areas for improved strength compared with standard composite driveshafts. It provides a practical balance of durability, low rotating weight and affordable replacement cost for off-road bashing and high-torque brushless applications.

The driveshaft arrives fully assembled with one screw pin and can be installed on either the left or right front side. One assembly is supplied, so two units are required when replacing both front driveshafts.

Features

• Extreme Heavy Duty Construction: Reinforced composite components add strength around critical load areas
• Front Driveshaft Assembly: Designed for the front axle position on compatible Traxxas vehicles
• Left or Right Installation: Fits either front side on compatible models
• Fully Assembled: Supplied pre-built and ready to install
• U-Joint Design: Allows the driveshaft to articulate as the steering and suspension move
• Composite Construction: Combines impact resistance with lower rotating weight than many steel alternatives
• Complete Axle Assembly: Replaces the driveshaft as a complete unit rather than requiring separate shaft components
• Screw Pin Included: Includes one installation screw pin
• Direct Replacement Application: Used as a factory replacement part on selected Traxxas models
• Durability Upgrade: Suitable for selected vehicles originally equipped with compatible standard-duty driveshafts
• Suitable for Brushless Use: Designed for demanding acceleration, jumping and off-road driving
• Genuine Traxxas Part: Manufactured to suit compatible Traxxas suspension and drivetrain dimensions

Specifications

• Brand: Traxxas
• Manufacturer Part Number: 6851A
• Product Type: Front RC driveshaft assembly
• Position: Front
• Side: Left or right
• Quantity: One driveshaft assembly
• Duty Rating: Extreme Heavy Duty
• Construction: Reinforced composite driveshaft with metal axle hardware
• Joint Type: U-joint
• Assembly Status: Fully assembled
• Screw Pin Included: Yes
• Installation Hardware Included: One screw pin
• Typical Vehicle Scale: Selected Traxxas 1/10 models

Compatibility

Confirmed replacement applications include selected versions of:

• Traxxas Hoss 4X4 VXL
• Traxxas Rustler 4X4
• Traxxas Rustler 4X4 VXL
• Traxxas Slash 4X4 Ultimate

Commonly referenced compatible model numbers include:

• Hoss 4X4 VXL 90076-4
• Rustler 4X4 67064-1
• Rustler 4X4 with LED lights 67064-61
• Rustler 4X4 VXL 67076-4
• Slash 4X4 Ultimate 68077-4

Traxxas model names may cover multiple generations and driveline configurations. Confirm part number 6851A in the vehicle’s exploded diagram or replacement-parts list before ordering.

Includes

• 1 × Traxxas front Extreme Heavy Duty driveshaft assembly
• 1 × Screw pin

Required to Complete

• Compatible Traxxas vehicle
• Suitable hex driver or hand tools for removal and installation
• Second Traxxas 6851A assembly when replacing both front driveshafts
• Thread-locking compound only where specified by the vehicle manual

FAQ

Does the Traxxas 6851A fit the left or right front side? It fits either the left or right front position on compatible vehicles.

How many driveshafts are included? One complete front driveshaft assembly is supplied. Order two when replacing both front driveshafts.

Is the driveshaft fully assembled? Yes. It arrives pre-assembled and ready to install.

Is the screw pin included? Yes. One screw pin is included with the driveshaft.

Is the Traxxas 6851A a steel driveshaft? No. It is an Extreme Heavy Duty reinforced composite driveshaft with metal axle hardware. Traxxas steel driveshafts are separate upgrade products.

Does it use a steel U-joint? Traxxas describes this as a composite Extreme Heavy Duty U-joint driveshaft. It should not be described as having an all-steel U-joint assembly.

What is the difference between Heavy Duty and Extreme Heavy Duty driveshafts? Extreme Heavy Duty shafts add composite material around critical stress areas to improve strength during hard acceleration, jumping and off-road impacts.

Can the 6851A replace the 6851X? It is commonly used as an Extreme Heavy Duty replacement or upgrade on selected models originally fitted with compatible front driveshafts. Confirm fitment against the exact vehicle revision before ordering.

Is this the correct driveshaft for the rear? No. Part 6851A is the front assembly. Traxxas 6852A is the corresponding rear Extreme Heavy Duty driveshaft for selected models.

Will it fit a Traxxas Slash 2WD? This part is primarily intended for selected 4X4 front applications. Do not assume compatibility with a 2WD vehicle without checking the model-specific parts diagram.

Should both front driveshafts be replaced together? It is not always necessary. Replace the damaged shaft and inspect the opposite side for twisting, cracks, joint wear or binding.

Why do front driveshafts break? Common causes include landing with the throttle applied, steering at full lock under heavy power, seized bearings, excessive suspension angles, oversized tyres and high-power upgrades.

Can steel driveshafts handle more power? Steel driveshafts generally provide greater power-handling potential but cost more and add rotating weight. Composite Extreme Heavy Duty shafts provide a useful balance of strength, weight and replacement cost.

What should be checked during installation? Inspect the differential output, bearings, steering block, suspension arm and wheel hardware. Confirm the shaft articulates and telescopes freely throughout the full steering and suspension range.

Does the driveshaft require lubrication? Keep the exposed joints clean and follow the vehicle manual. Heavy grease on exposed joints can attract dirt and create abrasive wear.

Important Notes

• One front driveshaft assembly is supplied, not a pair.
• The assembly fits either the left or right front position on compatible vehicles.
• Two units are required to replace both front driveshafts.
• This is a front driveshaft and is not interchangeable with every rear driveshaft application.
• The shaft is reinforced composite and should not be described as an all-steel driveshaft.
• Check the exact vehicle model number and exploded parts diagram before ordering.
• Traxxas model names may cover multiple generations with different factory components.
• Do not force the shaft into incompatible differential outputs, steering blocks or suspension components.
• Confirm that the shaft moves freely through the full steering and suspension range after installation.
• Check that the screw pin is secure before operating the vehicle.
• Use thread-locking compound only on metal-to-metal fasteners and only where recommended.
• Do not apply thread-locking compound to plastic threads.
• Inspect the steering blocks, hub bearings, differential outputs and suspension arms when replacing a broken driveshaft.
• Avoid applying full throttle while the steering is at full lock.
• Avoid applying throttle while the vehicle is airborne, inverted or while a wheel is obstructed.
• Oversized or heavy tyres can increase stress on driveshafts, differentials and wheel bearings.
• High-power motor and battery upgrades may exceed the intended load capacity of composite drivetrain components.