The Ford Mustang S550 is a vehicle that has captured the hearts of enthusiasts with its performance, style, and versatility. A key component of the S550’s performance is its rear differential system, particularly the Trac-Lock limited-slip differential. Proper tuning of the Trac-Lock system can elevate your driving experience, whether you’re on the track, cruising highways, or conquering backroads. In this guide, we’ll provide a comprehensive walkthrough on tuning the S550 Trac-Lock system, with tips, tricks, and tools for optimizing performance.
What is the Trac-Lock Differential?
The Trac-Lock is Ford’s limited-slip differential designed to enhance traction and stability. Unlike open differentials, which allow one wheel to spin freely when traction is lost, the Trac-Lock system uses clutch packs to distribute power between the rear wheels. This improves grip and performance in various driving scenarios, from acceleration to cornering.
Key Benefits of the Trac-Lock Differential:
- Improved traction during acceleration.
- Enhanced stability in cornering.
- Better control in slippery conditions.
- Reduced wheel slip for consistent performance.
Why Tune Your Trac-Lock Differential?
While the stock Trac-Lock system performs well for most drivers, tuning it can unlock significant performance gains tailored to your driving style. Whether you prioritize drag racing, road racing, or spirited street driving, proper tuning can:
- Optimize power distribution for specific conditions.
- Increase clutch pack durability.
- Improve handling and cornering dynamics.
- Reduce wear and tear on drivetrain components.
Tools and Equipment Needed
Before diving into the tuning process, ensure you have the following tools and supplies:
- Differential fluid (Ford’s Motorcraft 75W-85 or an equivalent high-performance alternative).
- Friction modifier (if not already included in your chosen fluid).
- Socket set and wrenches.
- Torque wrench.
- Differential gasket or RTV sealant.
- Drain pan and rags.
- Clutch pack rebuild kit (if upgrading or replacing worn parts).
- Owner’s manual or service manual for reference.
Step-by-Step Trac-Lock Tuning Guide
1. Assess the Condition of Your Differential
Before tuning, inspect the differential for wear and tear. Signs that your Trac-Lock may need servicing include:
- Excessive noise during turns.
- Uneven tire wear.
- Reduced traction or noticeable wheel slip.
Remove the differential cover and inspect the clutch packs for wear. If the clutches are worn, replace them with a rebuild kit to ensure optimal performance.
2. Choose the Right Differential Fluid
Selecting the correct fluid is critical for the Trac-Lock’s performance. Ford recommends Motorcraft 75W-85 gear oil, but you can opt for a high-performance alternative if you plan on aggressive driving. Always include a friction modifier unless your fluid already contains it.
- Street Use: Stick with OEM-recommended fluid for balanced performance.
- Track Use: Use a high-viscosity fluid to handle extreme heat and stress.
3. Adjust Preload and Clutch Pack Tension
The Trac-Lock system relies on clutch packs to limit slip between the rear wheels. Tuning these components can drastically affect performance.
- Increase Preload for Aggressive Locking: Add shims to the clutch packs to increase tension. This is ideal for drag racing, where maximum traction is crucial.
- Decrease Preload for Smooth Engagement: Remove shims to reduce tension, improving handling in road racing or street driving.
4. Install Upgraded Clutch Packs
For serious performance gains, consider upgrading to carbon-fiber or high-performance clutch packs. These materials offer better durability and heat resistance, making them ideal for high-stress applications.
5. Calibrate the Differential Settings
After mechanical adjustments, ensure the differential operates as intended by testing it in controlled conditions. Pay attention to:
- Lockup behavior during acceleration.
- Smoothness in cornering.
- Noise levels and heat generation.
6. Reassemble and Test Drive
Reinstall the differential cover using a new gasket or RTV sealant. Fill the differential with fluid and friction modifier, then torque the bolts to the manufacturer’s specifications. Take the vehicle for a test drive to evaluate performance and make further adjustments if necessary.
Trac-Lock Tuning for Specific Applications
Drag Racing
- Use a high-viscosity fluid to handle the intense forces of hard launches.
- Maximize clutch pack preload for quick and aggressive locking.
- Regularly inspect and replace worn components to maintain consistent performance.
Road Racing
- Opt for a medium-viscosity fluid to balance traction and smooth engagement.
- Reduce clutch pack preload for better cornering dynamics.
- Upgrade to carbon-fiber clutches for improved durability under continuous stress.
Daily Driving and Street Use
- Stick with OEM fluid and friction modifier for reliable performance.
- Maintain a moderate preload setting to balance traction and comfort.
- Perform regular maintenance to extend the life of the differential.
Comparison Chart: Trac-Lock Tuning Settings
| Application | Fluid Type | Preload Setting | Clutch Pack Material | Maintenance Frequency |
|---|---|---|---|---|
| Drag Racing | High-viscosity | Maximum preload | Carbon-fiber | Frequent (every 3-6 months) |
| Road Racing | Medium-viscosity | Moderate preload | Carbon-fiber | Moderate (every 6-12 months) |
| Daily Driving | OEM-recommended | Stock or mild preload | OEM or upgraded | Annual maintenance |
Conclusion: S550 Trac-Lock Tuning Guide
Tuning the S550 Trac-Lock Tuning Guide differential is a rewarding process that can dramatically improve your Mustang’s performance. Whether you’re chasing lap times or enhancing your daily driving experience, this guide provides the tools and knowledge to make informed decisions. Regular maintenance and thoughtful tuning will ensure your Trac-Lock system continues to deliver optimal performance for years to come.
FAQs
1. How often should I service the Trac-Lock differential?
Regular servicing every 12,000 to 20,000 miles is recommended for street use. For track use, inspect and service the differential more frequently to prevent component failure.
2. Can I tune the Trac-Lock without professional help?
Yes, with the right tools and knowledge, many enthusiasts can tune their Trac-Lock system at home. However, for complex adjustments or upgrades, professional assistance is advisable.
3. What are the signs of a failing Trac-Lock differential?
Common signs include:
- Clunking or grinding noises from the rear.
- Difficulty maintaining traction.
- Uneven tire wear.
