When it comes to maintaining the performance and reliability of a limited slip differential (LSD) in a Mopar vehicle, one often overlooked yet critical component is the Mopar limited slip additive. This small but essential fluid additive plays a major role in ensuring your vehicle’s differential operates smoothly, quietly, and without premature wear. Whether you drive a Dodge Challenger, a Jeep Grand Cherokee, or a Ram truck, understanding how and why to use this additive can make a big difference in your vehicle’s drivability and long-term health.
What Is Mopar Limited Slip Additive?
Mopar limited slip additive is a specially formulated friction modifier designed for use in vehicles equipped with a clutch-type limited slip differential. Limited slip differentials are engineered to distribute power to the wheel with the most traction, providing better handling and grip especially during acceleration, turning, or when driving in low-traction conditions like rain, snow, or gravel.
The additive helps reduce friction between the clutch plates inside the differential, preventing common problems like chatter, noise, and excessive wear. Without this additive, the plates may stick or grab during operation, leading to a harsh or jerky ride, and potentially shortening the lifespan of the differential components.
How It Works
Inside a limited slip differential, a series of clutch plates are responsible for transferring torque between the two rear wheels (or front wheels, depending on drivetrain). These plates must engage and disengage smoothly to maintain consistent traction and handling. The Mopar limited slip additive changes the friction characteristics of the differential fluid, allowing for smoother operation of these internal clutches.
The result is a quieter, more predictable driving experience, with reduced risk of mechanical issues caused by heat and stress buildup. For Mopar vehicles, this additive is calibrated to meet specific performance standards set by the manufacturer, making it an ideal choice for both factory service and aftermarket upgrades.
Signs You May Need the Additive
Drivers may experience symptoms that suggest a need for limited slip additive or a replacement of existing fluid. These include:
- Chatteringwhen turning corners, especially at low speeds.
- Clunking or popping soundsfrom the rear differential.
- Unusual vibrationsduring acceleration or tight turns.
- Reduced tractionin wet or loose surface conditions.
These signs often point to inadequate lubrication of the LSD clutch packs. Adding or replenishing the Mopar limited slip additive can usually resolve the issue if the fluid level and condition are otherwise acceptable.
When to Use the Additive
The Mopar limited slip additive is generally required whenever differential fluid is changed in a vehicle equipped with a clutch-type LSD. It should be added in the recommended amount alongside the base gear oil usually a high-quality synthetic 75W-90 or 75W-140 gear oil, depending on your vehicle’s specifications.
Even some synthetic gear oils claim to have friction modifiers built in, but for Mopar vehicles, it’s typically advised to still use the Mopar-brand additive for best results. This ensures compatibility and avoids issues with warranty or long-term component wear.
Application Instructions
Adding the limited slip additive is straightforward but should be done carefully. Here’s a general step-by-step guide:
- Safely raise and support the vehicle to access the differential.
- Remove the differential fill plug.
- If changing the fluid, remove the drain plug and allow old fluid to drain completely.
- Clean the fill and drain plugs, and reinstall the drain plug.
- Add the Mopar limited slip additive first, directly into the fill hole.
- Follow with the required amount of gear oil until fluid starts to seep out of the fill hole.
- Reinstall the fill plug and torque to factory specification.
It’s important not to overfill or underfill the differential, as this can cause leaks, pressure problems, or component damage. Always consult your owner’s manual or service guide for the exact fluid capacity and recommended products.
Compatibility and Product Numbers
The official Mopar limited slip additive is designed for use in all Chrysler, Dodge, Jeep, and Ram vehicles that are equipped with clutch-based limited slip differentials. It comes in a small bottle (usually 4 oz), and is typically identified by Mopar part number 4318060AD (previous versions may use suffixes like AA or AB).
Some differentials may require more than one bottle depending on the gear oil used and the application. Be sure to check whether your specific gear oil blend already contains friction modifier, and adjust accordingly.
Why Choose Mopar-Branded Additive?
There are several aftermarket friction modifiers available, but the Mopar limited slip additive is specifically engineered to work with Mopar differentials. Using a non-Mopar additive may work in the short term, but could lead to compatibility issues, noise, or reduced differential life over time.
Additionally, Mopar parts are covered under manufacturer warranty when used as part of scheduled maintenance or repairs, offering peace of mind and ensuring optimal performance. For vehicles still under warranty, using non-approved additives might jeopardize coverage if issues arise.
Tips for Optimal LSD Performance
- Always replace the differential fluid and additive at the intervals recommended by Mopar.
- Use high-quality gear oil that matches your climate and load conditions.
- Listen for signs of chatter or vibration and don’t ignore early warnings.
- Inspect differential seals and covers during service to prevent leaks.
- When towing or driving in off-road conditions, consider more frequent inspections.
Though it may seem like a small detail in the larger maintenance schedule, the Mopar limited slip additive plays a critical role in keeping your vehicle’s differential running smoothly and quietly. By reducing friction between internal clutch plates, it ensures better handling, increased traction, and a longer lifespan for your drivetrain components. Whether you’re performing regular maintenance or upgrading to a new limited slip differential, always include the correct amount of Mopar additive to get the best results from your vehicle. For Mopar enthusiasts and everyday drivers alike, this simple step makes a significant difference in performance and reliability.