Guide to gear oils

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3 Litre Power
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Car(s): 1975 Capri II 3000 Ghia factory manual, 505k kms, Sunset Red, BVR, B.I
1988 Ford Escort XR3i Cabrio, 177k kms, Red, Black Top ( Daily )
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Guide to gear oils

Post by 3 Litre Power »

GL-3 and GL-4 : Designed for manual gerboxes with brass parts such as synchronisers, it should only be used in Manual Gearboxes

GL-5 : Designed for Axles / Differentials , they contain twice the Phosphorous as GL-4 oils and they should NOT be used in gearboxes, because it will corrode the brass synchronisers and make them slip ( noisy shifting ), you can only use these in differentials, and reciprocally GL-4 should not be used in a differential because it lacks the Phosphorous Extreme Pressure additives.

GL-6 : not currently in use.

You may find some oils that are GL4 and GL5 rated, i would not use these and use an oil that only meets GL-4 instead ( ensures low amount of phosphorous ).
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