Dorman 600-305 4WD Actuator

Dorman 600-305 4WD Actuator Kit

The Dorman 600-305 4WD actuator kit restores vacuum-controlled hub engagement on select Ford and Lincoln trucks and SUVs. It addresses a common failure point in the original locking hub actuator by using an upgraded diaphragm material and a new vacuum solenoid for more consistent 4WD operation.

Compatible with Ford Expedition, Ford F-150, Lincoln Navigator, and Lincoln Mark LT applications that use an independent wheel end actuator, this OE FIX repair is built to match the original fit and function. The Dorman 600-305 is a direct repair solution for 4WD systems that stop engaging the inner axle shaft properly.

Key Features

• OE FIX 4WD actuator kit for vacuum-operated locking hub systems
• Upgraded diaphragm material resists wear and environmental contamination better than the factory design
• Includes a new vacuum solenoid for precise 4WD engagement
• Engineered to match original actuator and solenoid fitment
• Supports proper actuator vacuum performance and locking hub operation
• Rectangle female connector with 2 terminals
• Housing materials include steel and plastic

Detailed Description

This Dorman 4WD actuator kit is engineered for Ford Expedition and Ford F-150 models, as well as Lincoln Navigator and Lincoln Mark LT vehicles equipped with an independent wheel end actuator. It replaces the original hub locking actuator assembly with a revised diaphragm material that better resists fatigue and ozone-related deterioration, helping restore dependable vacuum control at the hub.

Part number 600-305 also includes a replacement vacuum solenoid to improve engagement timing and system response when 4WD is needed. This makes it a practical repair for drivers dealing with intermittent hub engagement, loss of front axle lockup, or a 4WD system that no longer responds correctly. This part cross-references OSC 4319 for the same application.

What It Helps Fix

• 4WD system failure to engage the front hubs
• Weak or inconsistent vacuum actuation at the locking hub
• Inner axle shaft not engaging properly
• Hub diaphragm wear from age, fatigue, or ozone exposure
• Delayed or unreliable 4WD response

Installation Notes and Tips

Verify the vehicle uses an independent wheel end actuator before ordering. Confirm connector style, terminal count, and mounting location against the original unit to ensure proper installation. Inspect vacuum lines, electrical connectors, and hub components for damage or leaks during replacement so the repaired system can operate correctly.

Quality Assurance

Dorman OE FIX parts are built as direct-fit replacement solutions that address known failure points in original equipment designs. Part number 600-305 is engineered to match the original actuator and solenoid fit for a complete repair on select Ford and Lincoln 4WD systems.