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Red Line Shockproof Gear Oil


This document has been put together to help you decide which of the Red Line SHOCKPROOF GEAR OILS are best for your vehicle or application. Here at Merlin we stock all three types; Heavy, Lightweight and Superlight in 1 U.S Quart (946ml) bottles.



Red Line SHOCKPROOF GEAR OIL is a unique transmission fluid that contains a suspension of solid microscopic particles that act as an extreme pressure agent. The viscosity characteristics allow the oil to resist throw off and provide a filmbetween the gear teeth preventing “shock”, “chatter” and tooth breakage in the transmission. A very popular range of gearbox and differential oils for highly loaded racing transmissions and “problem” gearboxes. The SHOCKPROOF GEAR OILS offer low drag and high protection. All three of the below oils are for use in wet sump gearboxes and differentials with splash lubrication. Please note: Due to the clagginess of the oil, it’s recommended this oil is not used in conjunction with oil coolers, oil pumps or oil filters as this can cause blocking of these components.


Superlight Shockproof Gear Oil

Superlight Shockproof gear oil has a viscosity of a 75W90 gear oil but has a lower internal friction, much like an ATF would have. This oil is used when temperatures are not massively high and the “shock” through the transmission is not too great. Used quite a lot in relatively low power vehicles where the gearbox/differential is not highly stressed. Formula Ford and similar categories that use a dog-ring type gearboxes are a good example. Not really recommended for use in synchromesh gearboxes due to its slipperiness.

Go to - Superlight Shockproof Gear Oil



Lightweight Shockproof Gear Oil

A step up from the Superlight version, this oil is recommended for vehicles with a moderate power output where the transmission will see higher loads, temperatures and “shock” than that of the Superlight oil. Similar to 75W140 gear oil but it has a lower internal friction like an 80W gear oil or 30W engine oil. Commonly used in saloon car transmissions with moderate power where the transmission does not see particularly high temperatures or “shock”. Good for use in racing differentials to obtain maximum power transfer. Not recommended for use in synchro-type transmissions.

Go to - Lightweight Shockproof Gear Oil


Heavy Shockproof Gear Oil

Used in serious powered vehicles like Drag Cars, Off-Road 4x4 or high power turbocharged cars etc which emit a high amount of torque through the transmission. This oil can be rated as a 75W250 while providing the same low fluid friction like a 75W90 would do. This is great for use in high temperature, high load and high “shock” transmissions as the Heavy gear oil does not thin like a regular gear oil would do, keeping its film between the gear teeth, acting as a cushion. As with the other two oils, the Heavy is not recommended for use with synchro applications due to its slipperiness.

Go to - Heavy Shockproof Gear Oil

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24th July 2018