Red Line Limited-Slip Friction Modifier & Break-In Additive - 118ml • 80301

Red Line 80301 Limited-Slip Friction Modifier & Break-In Additive - 118ml

Specialist Red Line differential additive for clutch-type limited-slip and Positraction differentials requiring additional friction modifier, as well as suitable new differential break-in applications.

Red Line Limited-Slip Friction Modifier is designed to alter the friction characteristics of the differential lubricant, helping eliminate clutch chatter while maintaining the controlled friction required for correct limited-slip differential operation.

For a differential experiencing limited-slip chatter, Red Line recommends adding approximately 1 US fluid ounce / 30ml at a time until the chatter disappears. Adding excessive friction modifier can reduce differential locking action, so the product should be introduced gradually rather than automatically adding the complete bottle.

The product can also be used as a differential break-in additive. Red Line states that it can reduce break-in temperatures by as much as 50°F / approximately 28°C, helping protect heavily loaded gear surfaces during the critical initial running period.

• Product type: Limited-slip differential friction modifier / break-in additive
• Brand: Red Line Synthetic Oil
• Product reference / SKU: 80301
• Container size: 118ml / 4 US fl oz
• Primary application: Clutch-type limited-slip / Positraction differentials
• Secondary application: New differential gear break-in
• Fluid compatibility: Petroleum and synthetic gear oils
• Chatter adjustment: Add approximately 1oz / 30ml at a time until chatter is eliminated
• Typical established LSD concentration: approximately 4%
• New differential break-in concentration: approximately 4–8%
• Break-in performance: Can reduce differential break-in temperatures by as much as approximately 50°F / 28°C
• GM performance requirement: 1052358
• Ford performance requirements: M2C118-A / 19B546-MA
• Chrysler performance requirement: 4318060

Fitment advice: This product is application-specific rather than vehicle-specific. It is intended for suitable clutch-type limited-slip / Positraction differentials where additional friction modifier is required, or for appropriate differential break-in procedures.

Dosage: For limited-slip chatter, add approximately 30ml at a time and reassess differential operation before adding more. Red Line recommends approximately 4% concentration for chatter prevention in an established differential and 4–8% for new differential break-in.

Important Red Line gear oil note: Most Red Line differential gear oils already contain limited-slip friction modifier. Red Line's NS gear oils are the principal exception. Additional modifier should therefore only be added when required by the differential or to correct limited-slip chatter.

ShockProof applications: Red Line also recommends an additional 3–6% of this additive in certain non-limited-slip racing differentials and quick-change units using Red Line ShockProof® Gear Oils.

Other items to consider: When servicing a differential, you may also want to consider the correct differential gear oil, replacement drain and fill plug washers, differential seals and related drivetrain service components where required.

Useful tools / consumables: Fluid transfer pump or filling bottle, graduated measuring container, drain pan, suitable sockets or spanners, torque wrench, protective gloves and workshop towels.

Difficulty guide: DIY Difficulty: Moderate. Adding friction modifier is straightforward, but determining the correct quantity requires care because excessive modifier can adversely affect limited-slip locking characteristics.

Why Red Line? Red Line Synthetic Oil is known for high-performance lubricants, fluids and additives developed for demanding road, track and motorsport use. Red Line products are chosen by enthusiasts and workshops for their focus on protection, thermal stability, friction control and application-specific performance.

What’s in the bottle: One 118ml / 4 US fl oz bottle of Red Line Limited-Slip Friction Modifier / Break-In Additive.

Service notes: Add the minimum quantity necessary to achieve correct differential operation. After adding friction modifier, operate the vehicle sufficiently to circulate the additive through the differential before assessing whether any additional quantity is required.