Gearbox oil: Which grade to use?

There is always some doubt in what type of oil should be used in a 500, 126 and a126 BIS gearbox. If you are not sure what gearbox you have a simple rule of thumb is, if the gearbox has synchromesh then it’s from a 126 (or 126 BIS) and if it’s a ‘crash box’ then it’s a 500! Model Fiat recommend Equivalent 500 all models TUTELA W 90/M SAE 90 EP 126 all models inc. BIS TUTELA ZC 90 SAE 90 EP means extreme pressure and refers to the additive in the oil. The additive is to stop metal-to-metal … Continue reading Gearbox oil: Which grade to use?