© 1988, 1997, 2000 Red Line Synthetic Oil Corp.

IMPROVED LOW TEMPERATURE FLUIDITY
Cold weather can be just as damaging to differentials
and transmissions as sustained high-temperature use.
Rapid oil flow to the bearings and adequate lubricant
splashed to the gear teeth is critical to prevent component fatigue and premature failure. At -15°F an SAE 90
gear oil will take more than 5 minutes to flow to thebearings while Red Line 75W90 requires only a second.
This dry lubrication can cause rapid fatigue damage.
High viscosities when cold will also rob the vehicle ofconsiderable power until the lubricant has fully warmedup. Figure 2 below shows how Red Line Gear Oils compare to petroleum gear oils at 0°C.
LOW-TEMPERATURE
FLOW COMPARISON @ 0°C

Petroleum 85W140

and reducing temperatures. The relatively constant viscosity of Red Line Gear Oils compared to petroleums
also provides a significant increase in efficiency. Figure
3 demonstrates how the low temperature viscosity feature provides a tremendous improvement in efficiency
during short trip and low-speed service, yet even when
the temperature has stabilized, a 2.5% efficiency
improvement resulted from the replacement of the SAE
90 gear oil with the synthetic 75W90 in this European
sedan. The ambient temperature during this test was0°C(32°F) and both the transmission and differential
lubricants were replaced with the 75W90. Even at stabilized temperatures or elevated temperatures resulting
from heavy loads or high speeds, the higher viscosity athigher temperatures and improved slipperiness resultsin improved efficiency. Figure 4 below shows an axle
efficiency evaluation comparing the synthetic gear oilsto petroleum gear oils in a heavy-duty truck axle operated at its rated load. Red Line Gear Oils can provide asignificant improvement in power transfer and fuel economy, while at the same time providing thicker oil films in
the high-temperature contact zone which improves drivetrain durability. This feature has allowed Red Line toestablish a reputation in auto racing as providing theGEAR OIL EFFICIENCY COMPARISONIMPROVED DRIVETRAIN EFFICIENCY
A combination of features of Red Line Gear Oils provides greater operating efficiency. Improved slipperinessin the gear tooth contact zone provides a significant friction reduction - improving power transfer
75W90 Fuel Efficiency Improvement
vs. Petroleum SAE 90
20Axle Efficiency, %100

0% Fuel Efficiency Improvement

3Petroleum 85W140

5Red Line 80W140

7Petroleum 80W90

9Red Line 80W140 Gear Oil

2500

Petroleum 80W90

5000

Red Line 75W90 Gear Oil

10000

Red Line Light Weight Gear Oil

Viscosity, cP @ 0°C

15000

High-Temperature Viscosity Protection

Red Line 75W90

the greatest gear protection available• Provides
differential and gearbox temperatures• Reducesdifferential and gearbox durability• Increases
lubrication even in very cold weather• Rapid
shifting in manual transmissions• Improves
improved drivetrain efficiency• Provides
foaming even at high speeds• Prevents
corrosiveness reduces synchronizer wear
• Loweven at elevated temperatures• Stablebe used in limited-slip and regular differentials• Can
for competition and street use• Suitablewith petroleum and other synthetics• Compatible
with seals designed for petroleum• Compatible
requirements calling for API GL-5 and GL-6
• Satisfies• Allows extended drains in non-warranty vehicles

Red Line Light Weight

BENEFIT SUMMARY

IMPROVED GEAR PROTECTION
Proper differential and transmission lubrication requires
a product which will satisfy a wide range of service conditions. The off-set gear intersection design in hypoid
differentials requires a high degree of extreme pressurechemistry to prevent scoring of the ring and pinion set
under high-speed conditions and spalling under lowspeed / high-torque conditions. High temperatures cancause a breakdown of the petroleum, forming insoluble
sludge which can plug the bearing cages and cause oilstarvation to the bearing surfaces. Limited-slip clutches
require additional slipperiness compared to conventional
hypoid differentials in order to prevent the noise andvibration producing stick/slip phenomenon. Most ofthese friction modifier supplements detract from theload-carrying capability of the lubricant. Red Line's
75W90 and 80W140 Gear Oils have been developed to
be used in both conventional and limited-slip differentials, providing additional slipperiness for the limited-slipunits and also enhance the load-carrying capacity of thegear oils. The synthetic components used provide a naturally high viscosity index, which means that Red Line
Gear Oils have a relatively constant viscosity withchanging temperature. They will not thin out as readily
at high temperatures when compared to petroleums andthey are much more fluid at low temperatures. Figure 1
compares the high temperature oil film thickness of Red
Line Gear Oils compared to petroleum products. Note
how Red Line 75W90 provides a much greater viscosity
than a petroleum 80W90 (SAE 90). The contact zone
temperature can be several hundred degrees greaterthan the bulk oil temperature. This difference in hightemperature viscosity and the ability to more effectively
lubricate in extreme temperatures may prevent oil film
rupture at high temperatures and loads.

Viscosity, cSt @ 300°F

RED LINE SYNTHETIC GEAR OILS are designed toprovide the highest degree of protection and greatest
efficiency for your drivetrain. Red Line provides a complete line of drivetrain lubricants which are optimized for
differential, transmission, or transaxle use over a wide
range of temperatures. Proper selection depends upon
the manufacturers' requirements and whether the application is for passenger automotive, commercial, or racing use. Red Line Gear Oils contain polyol ester basestocks, the only lubricants which can withstand thetremendous heat of modern jet engines, which makes
our products provide excellent lubrication even under
extreme conditions of high-loading and high-temperatures. The natural lubricity of the polyol esters provide
excellent slipperiness which reduces the sliding friction
in hypoid gears - reducing wear and significantly reducing temperatures. The synthetic basestocks have a natural multigrade property, so large amounts of unstablethickeners are not required to manufacture our gear oils,
which means that Red Line Gear Oils will provide a stable viscosity for even extended periods of use. Red Line
formulates more extreme-pressure protection into thegear oils than other petroleum and synthetic manufacturers which provides wear protection over a wider
range of temperatures and performance conditions ranging from high-torque and low-speed situations tovery high-speed conditions with shock loading. Red Linealso manufactures gear oils which can be used in limited-slip differentials without the use of additional frictionmodifiers.

Red Line 75W90
Red Line 80W140

989694

Petroleum 80W90
Petroleum 85W140

92

90
0Average Improvement = 4.5 %Minimum Improvement = 2.5 %

150246810
Trip Mileage

12203040

5060

Miles/Hour

10864201014

best power and greatest equipment durability of any
lubricants available. Red Line Gear Oils usually provide
greater than twice the component durability in high-performance applications. These synthetics have demonstrated fuel economy savings as great as 5% in intercity
freight hauling and between 0.5% - 3% in line haul
trucking operations. The fuel savings alone provide areturn many times greater than the cost of the synthetic
lubricant.

REDUCES TEMPERATURESThe enhanced lubricity and better heat transfer capability of the synthetics enables Red Line Gear Oils toreduce axle temperatures to insure a thicker oil film inthe contact zone and provide better equipment durability. Red Line Gear Oils will reduce differential temperatures between 10 - 70°F and transmission temperatures
between 10 - 50°F. The actual degree of temperature
reduction depends on the speed and load conditions ofthe equipment - with more stressful conditions showing
greater differences. Even greater temperature reductions can be seen when comparing axle break-in temperatures. The friction modifiers allow a more gradualwearing in of mating surfaces, significantly reducing
break-in temperatures and minimizing potential problems associated with a loss of hardness of the gear
tooth surfaces. Friction tests have shown Red Line
Gear Oils provide a 15% reduction in the coefficient offriction compared to good synthetic and petroleum gearoils. Seal durability is another problem associated withhigh temperatures. Many seal materials will harden at
temperatures above 250°F, causing cracking and theleakage of fluid.
CORROSION PROTECTION
The extreme pressure chemistry used in many gear oils
can be corrosive to brass and bronze used in synchronizers and bushings. Most gear oils are corrosive attemperatures of 200°F. Red Line Gear Oils are non-corrosive up to 300°F and the MTL® in excess of 375°F. A
corrosive gear oil can shorten synchronizer life by halfand can also contribute to rust problems.
THERMAL STABILITY
The thermally stable components used in Red Line
Gear Oils insures stability even under elevated temperatures. Petroleum gear oils will form insoluble deposits
which can interrupt the flow of oil to the bearings andgears, causing premature failure. These deposits canalso be abrasive to the seals and cause leakage. RedLine Gear Oils are capable of being used many times
longer than petroleum gear oils. These gear oils havebeen used in heavy-duty trucks for 250,000 miles withexcellent cleanliness and durability.
SEAL AND LUBRICANT COMPATIBILITY
Red Line Gear Oils are designed to be compatible withseals which were designed for use with petroleum products. Reduced temperatures and improved deposit control should allow longer seal life. Red Line Gear Oils arecompatible with petroleum and most other synthetics,
so flushing is not required.
LIMITED-SLIP COMPATIBILITY
Red Line Gear Oils, with the exception of the75W90NS, and 75W140NS, already contain friction
modifier required for operation in limited-slip differentials. Additional additive is not usually required, but
newer units or those with more lockup capability may
require 1-4% additional Red Line Limited-Slip Friction
Modifier. If Red Line is not available, the manufacturers
recommended friciton modifier is compatible. Do not
add addtional modifier unless necessary, as too much
will result in excessive wheel spin. To perfectly tune adifferential, start with the 75W90 NS or 75W140 NS and

add the Red Line Limited-Slip Friciton Modifier until thelimited-slip chattering just disappears.
PRODUCT APPLICATION
75W90 Gear Oil - the preferred product in nearly all car
and light truck differentials, both conventional and limited-slip. 75W90 is preferred for most racing applications.
It contains friction modifier which is recommended forlimited-slip units. 75W90 Gear Oil can be used in manytransmissions and transaxles; however, other Red Linelubricants have better frictional properties for rapid synchronization. Exceeds API GL-5.
75W90 NS, 75W140NS - GL-5 lubricants which do notcontain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers cometo equal speeds more quickly, allowing faster shifting andmuch easier low-temperature shifting. Can also be usedin racing limited-slip differentials where weak spring
design causes too much wheel spin. These products provide significantly more lockup. Some Limited-Slip Friction
Modifier may be required for optimum preformance.
80W140 Gear Oil - generally used in commercial trucks
which will climb long, steep grades and some racing
applications where power is not critical. Generally 0.5%
less efficient than 75W90. Can also be used in differentials and transmissions where excessive noise is a problem and limited-slip differentials which vibrate excessively when turning a corner. Exceeds API GL-5.
LightWeight Gear Oil - a 75W/80W GL-5 gear oil
designed to lubricate transmissions and transaxles which
recommend 80W GL-5 gear oils. It has excellent lowtemperature flow which allows easier shifting when cold.
Also has good synchro compatibility. May be used toobtain maximum power transfer in racing differentials
which do not see high temperatures.
SuperLight Gear Oil - a 70W/75W GL-5 gear oil with theviscosity of an ATF. This is used when temperatures are
not high and when the maximum power output isrequired such as in qualifying laps.
ShockProof™ EP Gear Oil - a unique lubricant containing a suspension of solid microscopic particles as anextreme pressure agent. The viscosity characteristics
allow the lubricant to resist throwoff and provide a film
thickness greater than an SAE 250 grade, with the same
low fluid friction as with the 75W90. Recom-mended foroff-road racing and problem gearboxes. Also available inLightWeight and SuperLight viscosities.
MTL® - Manual Transmission/Transaxle Lubricant.
A 75W/80W GL-4 gear oil which is designed for manualtransmissions which require 75W or 80W GL-4 gear oils,
motor oils, or most special synchromesh fluids. It provides low temperature shiftability equal to an ATF, yetwill not thin out or shear at high temperatures and provides the substantial gear protection of a GL-4 gear oil.
The higher synchronizer coefficient of friction allows
faster upshifting and downshifting and the lubricant is
non-corrosive to synchros and bushings.
MT-90 - Manual Transmission/Transaxle Lubricant.
A 75W90 GL-4 gear oil which is designed for manualtransmissions which require 75W90, or 90 GL-4 gear oils
or motor oils. Uses the same chemistry as MTL® , but isa 90 WT in order to satisfy certain manufacturers which
recommend SAE 90 GL-4 gear oils.
ATF - a full synthetic automatic transmission fluid which
is a registered Dexron II, Mercon, and Mercedes-Benz
236.8 fluid and suitable for use in most automatic transmissions. Its benefits include better thermal and oxidation stability which make it perfect for vehicles which
see high temperatures. It also flows much better in low
temperatures, providing tremendously improved shifting
when cold.
D4 ATF - synthetic ATF for use where Dexron III orMercon is recommended. A higher viscosity allows optimal operation at 40°F higher temperature, providing
better torque converter efficiency. Provides wear protection of a GL-4 gear oil. Perfect for all modern automaticand manual transmissions which call for Dexron III orMercon ATFs. Superior stability allows high-temperature operation without varnishing valves and clutches
which causes failure. Provides the far better low-temperature operation compared to a conventional ATF.
HIGH-TEMP ATF - synthetic ATF for use where Dexron
III or Mercon is recommended. A higher viscosity allows
optimal operation at 70°F higher temperature, providing
better torque converter efficiency. Provides wear protection of a GL-4 gear oil. Perfect for heavily-loaded vehicles and automatic transaxles. Superior stability allows
high-temperature operation without varnishing valvesand clutches which causes failure. Provides the same
low-temperature operation as with a conventional ATF.
RACING ATF - synthetic ATF for automatic and manualtransmissions which need the positive shift of a TYPE-F
ATF. This ATF contains no slipperiness additives, producing faster shifts and quicker lock-up. A higher viscosity at high temperatures provides greater torque converter efficiency and the enhanced extreme-pressure
protection provides five-times the film-strength ofpetroleum and other synthetic ATFs.
DIFFERENTIALS - 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. LightWeight or SuperLight can beused to obtain maximum power transfer in racing differentials which do not see high temperatures.
TRANSMISSIONS - MTL® can be used in most manualtransmissions and transaxles for both street and racing
use unless the manufacturer requires the additional protection of an SAE 90 or the extreme-pressure protectionof a GL-5. In those situations the MT-90 (GL-4) or
75W90NS (GL-5) will provide good shiftability and synchro compatibility and extra gear protection.
LightWeight Gear Oil can be used in transmissions calling for a 75W or 80W GL-5. 75W140NS will provide
greater high-temperature viscosity, reducing gear noiseand rattle. D4 ATF can be used where the manufacturer
calls for an ATF as the D4 has GL-4 gear protection
and provides the best low-temperature shiftability.

RED LINE®

SYNTHETICGEAR OILSTECHNICALINFORMATIONRed Line Synthetic Oil Corp.
6100 Egret Court, Benicia, CA 94510(707) 745-6100© 1988, 1991, 2002 Red Line Synthetic Oil Corp.