You must consult your vehicle's owner's manual for the precise amount of fluid required. The manual will specify the correct capacity for your particular differential. Failing to use the correct amount can lead to damage.
If you don't have the owner's manual, you can try:
* Searching online: Use your vehicle's year, make, model, and engine size to find a repair manual or online forum where this information might be available.
* Checking a parts store: Auto parts stores often have online databases or knowledgeable staff who can look up the correct fluid capacity based on your vehicle's information.
Never guess the amount of fluid. Overfilling can cause seals to leak and damage internal components. Underfilling can lead to insufficient lubrication and component failure. Accurate measurement is crucial.