WRX diff oil

I'm looking to change the diff oil to a synthetic as it gets really cold here. I've checked past posts and a lot of people seem to prefer the Redline 75W90ns. Now, I've read the info on Redline's website and they state the the NS is for non-limited slip diffs, though it is GL5. Shouldn't I go with the straight 75W90 though?

Reply to
tom
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With the RedLine synthetics, you would want to use the 75W90NS in the transmission (it's less slippery, and is better for the synchro's) and can use the regular 75W90 in the rear differential - they are both GL-5 rated. (realistically, either one is probably fine in the differential - the limited slip part is sealed from the rest - it isn't lubricated by the gear oil you put in there)

Reply to
David & Caroline

Reply to
Edward Hayes

As long as you stay away from the MT90 and MTL, you are fine.

from

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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 for limited-slip units. 75W90 Gear Oil can be used in many transmissions and transaxles; however, other Red Line lubricants have better frictional properties for rapid synchronization. Exceeds API GL-5.

75W90 NS - a GL-5 which does not contain the friction modifiers for limited-slip hypoid differentials. This makes the transmission synchronizers come to equal speeds more quickly, allowing faster shifting and much easier low-temperature shifting. Can also be used in racing limited-slip differentials where weak spring design causes too much wheel spin.

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 low- temperature flow which allows easier shifting when cold. Also has good synchro compatibility. May be used to obtain maximum power transfer in racing differentials which do not see high temperatures.

SuperLight Gear Oil - a 70W/75W GL-5 gear oil with the viscosity of an ATF. This is used when temperatures are not high and when the maximum power output is required such as in qualifying laps.

ShockProofTM Gear Oil - a unique lubricant containing a suspension of solid microscopic particles as an extreme 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 our 80W140. Recommended for offroad racing and problem gearboxes.

MTL® - Manual Transmission/Transaxle Lubricant. A 70W80 GL-4 gear oil which is designed for manual transmissions which require 70W - 80W GL-4 gear oils, motor oils, or ATFs. It provides low temperature shiftability equal to an ATF, yet will 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 manual transmissions which require 75W90, or 90 GL-4 gear oils or motor oils. Uses the same chemistry as MTL , but is a 90 WT in order to satisfy certain manufacturers which recommend SAE 90 GL-4 gear oils.

Reply to
David & Caroline

I had the same problem with redline, no answers to emails. I ended up with Amsoil because I drive mostly highway.

Reply to
blazing lazers

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