NC Miata Differential Oil
Differential Capacity
~0.63-0.85 qt
~0.6-0.8 L
Differential Lubrication Specifications:
API service GL-5
Add the specified oil through the oil-fill plug hole until the oil level reaches the lower end of the plug hole. Replace the washers on the drain and fill plugs each time the oil is changed.
The factory service manual lists the following viscosities: SAE 90, SAE 80W-90, SAE 75W-90 (Not available from Mazda). If the oil level is lower than approx. 12 mm {0.47 in} from the lower end of the oil-fill plug hole, inspect for oil leakage and add the specified oil.
Sources: