Important Considerations:
* Type of Differential: Make absolutely sure you have the correct type of differential. Some Rangers had limited-slip differentials, requiring a specific type of gear oil (often a friction modifier additive is included). Check your owner's manual or the differential itself for markings to confirm.
* Fill Plug Location: Locate the fill plug (usually a slightly larger bolt than the drain plug) before you begin draining the oil. You'll need a wrench or socket that fits.
* Drain Plug Location: Locate the drain plug. Place a drain pan underneath to catch the old oil.
* Overfilling: Overfilling the differential can cause damage. It's better to slightly underfill and then check the level after running the vehicle. The fill plug should have a level hole or be at the proper level when filled correctly.
* Safety: Allow the oil to cool before working on the differential. Wear gloves to avoid skin contact with the used oil. Dispose of used oil properly at a recycling center.
Procedure (General):
1. Warm up the differential: A short drive will help thin the oil, allowing for easier draining.
2. Locate and remove the drain plug: Place a drain pan underneath.
3. Drain the old oil: Allow it to drain completely.
4. Locate and remove the fill plug: This allows air to escape during filling.
5. Install the drain plug: Tighten securely.
6. Add the new oil: Refer to your owner's manual for the correct quantity. Use a funnel to avoid spills. You can check the level using the fill hole if it is designed for that, otherwise you'll likely need to look at the fill plug location to approximate the correct level.
7. Install the fill plug: Tighten securely.
8. Check the fluid level after a short drive: You might need to add a bit more oil.
Always consult your owner's manual for the specific recommendations for your 1999 Ford Ranger 2.5L. This information is for general guidance only.
