Millers Classic Differential Oil EP 90 GL5

SAE 90 GL-5 differential oil for classic hypoid transmissions

Millers Classic Differential Oil EP 90 GL5 is a mineral SAE 90 differential oil with extreme-pressure additives, developed for hypoid differentials and heavily loaded hypoid transmissions.

It can also be used in transmissions with brass and bronze components, and is sold in 1 L and 5 L packs.

Key properties

• Grade: SAE 90, API GL-5, MIL-L-2105D, mineral base oil
• Viscosity: 153 cSt at 40 °C, 15.4 cSt at 100 °C, viscosity index 102
• Specific gravity 0.893 at 15 °C, pour point -18 °C, flash point 205 °C
• Suitable for brass and bronze components, according to Millers Oils
• High load-carrying capacity
• Packs: 1 L and 5 L

Choosing the right oil

This is the lighter sibling of the 85W-140 differential oil. SAE 90 at GL-5 is what the rear axles of many older cars call for, so check the handbook for the number: if it says 90 and GL-5, this fits. If it says 80W-90 and GL-4, the Millers Classic Gear Oil EP 80W90 GL4 is the closer match; if it names 85W-140, use that grade.

The mention of brass and bronze components means it can be used in transmissions with those parts, but it is still a GL-5 oil. Gearboxes with yellow-metal synchromesh parts that were designed for GL-4 are better served by a GL-4 oil.

Use it undiluted, and drain and refill according to your service schedule.