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Demon Tweeks£28.91Visit shop Red Line 75W140NS GL-5 Gear Oil - 1 Quart (0.946 Litre)
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The Red Line 75W-140 NS GL-5 Gear Oil is a fully synthetic lubricant designed for vintage and historic vehicles with synchro gearboxes, offering superior protection and optimal performance. Its high viscosity index ensures consistent film thickness across temperature ranges, while its formulation without friction modifiers provides maximum differential lock-up for competition use. A potential consideration is its specific API GL-5 rating, which may not be suitable for all transmissions. Key features include its synthetic base, GL-5 compliance, and suitability for limited-slip differentials.
| Model Part Number | 57109 |
|---|---|
| Brand | Red Line |
No. It is specifically designed for API GL-5 applications, including many vintage gearboxes and competition differentials. It is NOT recommended for transmissions that specify API GL-4, as the GL-5 additives can damage yellow metals found in those synchronizers.
It is strongly recommended to only mix Red Line 75W-140 NS GL-5 with other Red Line synthetic gear oils (like 75W90NS or MT-90) to adjust viscosity. Mixing with conventional mineral oils can compromise the performance and protective qualities of the synthetic base.
NS stands for 'Non-Slip', indicating that the oil does not contain friction modifiers, making it ideal for limited-slip differentials that require maximum lock-up.
Always consult your vehicle's owner's manual or a reputable service manual for the correct API specification. If unsure, particularly with older vehicles, it is safer to assume GL-4 or consult a specialist, as GL-5 can damage GL-4 specific components.
The 'NS' in this product's name signifies its 'Non-Slip' formulation, meaning it lacks friction modifiers. Other Red Line 75W-140 oils may contain friction modifiers suitable for street-driven limited-slip differentials that require smoother engagement and quieter operation.
Yes, as long as the differential requires an API GL-5 lubricant, this oil can be used. Its robust protection and high viscosity are beneficial for standard differentials as well.
Follow your vehicle manufacturer's recommendations for fluid change intervals. For vintage or competition vehicles, more frequent changes may be advisable based on usage and operating conditions.
Ensure the correct oil viscosity and API rating are used. If the gearbox originally specified GL-4, GL-5 may cause synchronization issues. Verify compatibility or consider a GL-4 specific oil.
This oil is designed for maximum lock-up and contains no friction modifiers. If you are experiencing *lack* of lock-up, ensure the LSD clutches are not worn out. If you are experiencing *too much* lock-up or chatter, and this is undesirable, a different oil formulation may be needed.
While synthetic oils can sometimes cause older seals to swell or shrink, check the condition of your seals. If seals are old or brittle, replacement may be necessary. Ensure the correct fill level is maintained; overfilling can stress seals.
The 75W-140 NS is a relatively thick oil. If noise persists or worsens, try blending with a lighter Red Line gear oil like 75W90NS or MT-90 in a 50/50 ratio to adjust viscosity and potentially quieten the gears. Ensure no internal mechanical issues are present.
Compatibility: This oil is specifically recommended for API GL-5 applications, particularly vintage and historic synchro gearboxes (mid-1930s to early 1950s) and competition cars with plate-type limited-slip differentials. Crucially, verify your vehicle's specific lubricant requirements. API GL-5 oils contain extreme pressure additives that can damage yellow metals (like brass and bronze synchronizers) found in some older transmissions, especially those originally designed for API GL-4 specifications. Consult your vehicle's service manual or a specialist if unsure.
Setup: Ensure the gearbox and differential are clean and free from contaminants before filling. Use the appropriate transfer pump or funnel to fill the unit to the manufacturer's recommended level, typically up to the bottom of the fill plug opening.
Care: Store the sealed container in a cool, dry place away from direct sunlight. Once opened, use the product promptly. Regular inspection of the gearbox and differential for leaks is recommended. There are no specific maintenance intervals for the oil itself beyond the standard fluid change recommendations provided by the vehicle manufacturer, which may vary significantly based on usage.
