Here's why:
* Different functions: The engine oil lubricates the moving parts within the engine, while the gearbox oil lubricates the gears and bearings within the transmission.
* Separate systems: The engine and transmission are two separate systems with their own oil reservoirs and lubrication circuits.
However, the gearbox oil and engine oil should not be mixed. They are different types of oil with different properties and functions.
It's important to ensure you use the correct type of oil for each system. Refer to your owner's manual or a reputable service manual for specific oil recommendations for your 2002 1.4 Astra.
