Differential Oils

Red Line Gear Oils are designed to provide excellent low-temperature characteristics and improved gear protection at higher temperatures. 

Red Line Gear Oils will reduce differential temperatures 10-70°F. Efficiency improvements between 1-5% are typical. The synthetic base stocks used have tremendous thermal stability and provide the best film strength available. The unique combination of base stocks and additives allow Red Line gear oils to carry higher loads compared to petroleum lubricants. The stability of these products allow them to be used for extended periods.  

Red Line 75W90 Gear Oil provides excellent protection in nearly all differentials, conventional and limited slip, in both racing and street use. 75W90NS and 75W140NS can be used in certain limited-slip units in racing to lock-up the differential. 80W140 should be used in commercial hauling, problem limited-slip units, racing applications which see tremendous torque at low speeds, and where noise deadening is desired. The 75W85 or SuperLight can be used to obtain maximum power transfer in racing differentials which do not see extremely high temperatures. If “chattering” occurs with any of these lubricants, 

Red Line Limited Slip Friction Modifier can be used to eliminate the stick/slip action and reduce the noise. This additive should not be necessary in the 75W90, 75W140 or the 80W140 Gear Oils, since they already contain this additive, but in some units more is required.

All of the Differential Products Feature:

• Fully-synthetic formulas created from polyol ester base stocks, offer excellent lubrication under extreme conditions
• High viscosity-index (VI) to provide relatively constant viscosity and film thickness with varying temperature change
• Ester base stocks and friction modifiers provide additional slipperiness to lower operating temperatures by reducing the sliding friction in hypoid gears
• Superior shear stability and reduced oxidation compared to other synthetics and conventional gear oils
• Exceed API GL-5 specifications
• Engineered to provide the highest degree of protection and improvement of differential efficiency for better mileage, longer drain intervals, and less wear

75W90 (GL-5)

• Most popular Red Line gear oil, with thousands of applications for
  passenger cars, light trucks, and racing vehicles
• Contains additional friction modifiers for suitability with clutch-type
  limited slip differentials - for most LSDs, no additional friction modifiers
  are required
• This product is not designed for use in most manual transmissions or transaxles in passenger vehicles, since the extreme slipperiness may 
  cause synchronizer mesh issues that lead to shifting problems
• Recommended for API GL-5, GL-6, MT-1, MIL-L-2105E, SAE J2360,
  and Chrysler spec MS-9763

75W90NS (GL-5)

• Designed for transmissions and transaxles - helps to slow synchros for easier shifting across a broad temperature range
• Popular in Ferrari, Porsche and Subaru transaxles
• Musclecar applications like Ford Top Loader, Borg-Warner T-10 
  and Super T-10, and Muncie transmissions
• Contains extreme pressure additives like our 75W90 GL-5 oil, but lacks friction modifiers to balance slipperiness
• Improved copper corrosion protection to prolong synchro life
• Helps with lock-up on weak limited-slip differentials-compatible with 
  Red Line Limited Slip Friction Modifier for tuning slippage
• Also used with clutch-type LSDs in racing for maximum lock up
• Recommended for API GL-5, GL-6, MT-1, MIL-L-2105E and SAE J2360

75W140 (GL-5)

• Popular for cars and light trucks like Ford Mustang, Ford F-150, 
  Dodge Ram, Toyota Tundra and Sequoia, and Jeep Cherokee
• Contains additional friction modifiers for suitablity with clutch-type limited 
  slip differentials - for most LSDs, no additional friction modifiers are required
• This product is not designed for use in most manual transmissions or tranaxles, since the extreme slipperiness may cause synchronizer mesh issues that lead to shifting problems
• Recommended for API GL-5, GL-6, MT-1, MIL-L-2105E, and SAE J2360

75W140NS (GL-5)

• Contains extreme pressure additives like our 75W140 GL-5 oil, but lacks friction modifiers to balance slipperiness
• Popular for historic and vintage transmissions, like Mid-1930s to 
  early-1950s synchro-equipped gearboxes in cars and trucks
• Helps with noisy or rough shifting in troubled A-833 Dodge/Plymouth
  4-speed transmissions from 1964 to 1969
• Option for noisy transmissions when mixed with 75W90NS
  or MT-90 to bring viscosity level up
• Also used in clutch-type limited slip differentials in racing for maximum
  lock up-some users add Limited Slip Friction Modifier in small doses to customize slippage
• Recommended for API GL-5, GL-6, MT-1, MIL-L-2105E, and SAE J2360

75W85 (GL-5)

• Popular in many Toyota light truck differentials and transfer cases
• Also popular in many Formula racing transaxles, including
  Hewland LD-200 and FTR sequential
• Contains additional friction modifiers for suitablity with clutch-type limited
  slip differentials - for most LSDs, no additional friction modifiers are required
• This product is not designed for use in most manual transmissions or tranaxles with synchronizers, as extreme slipperiness may cause shifting problems
• Known formerly as Lightweight Gear Oil
• Satisfies the gear oil viscosity requirements of SAE 75W80, 75W, 80W,
  and 85W, as well as SAE 30 and SAE 10W30 motor oil
• Recommended for API GL-5, GL-6, MT-1, MIL-L2105E, and SAE J2360

Friction Modifier

• Compatible with both petroleum and synthetic gear oils
• Reduces break-in temps as much as 50°F
• Add 1oz at a time to clutch-type limited slip or posi-traction
  units to eliminate chatter