Tools You'll Need:
* Jack and jack stands: Essential for safety. Never work under a vehicle supported only by a jack.
* Wheel chocks: To secure the front wheels.
* Wrench(es): You'll need a socket wrench and sockets to fit the drain plug and fill plug. The sizes are typically 10mm, 11mm, or possibly 3/8" or 7/16" – check your owner's manual. A box-end wrench can be helpful as well.
* Drain pan: To catch the old fluid.
* Funnel: To add the new fluid.
* New rear differential fluid: The correct type and amount are specified in your owner's manual. This is usually a 75W-90 gear oil, possibly with limited-slip additive if your truck has a limited-slip differential.
* Torque wrench: Crucial for tightening the drain and fill plugs to the correct specification to prevent leaks.
* Gloves: To protect your hands from the dirty fluid.
* Rags or shop towels: For cleanup.
* Optional: Pump for filling: Makes adding fluid cleaner.
Procedure:
1. Safety First: Park your truck on a level surface, engage the parking brake firmly, and chock the front wheels. Wear safety glasses.
2. Locate the Differential: The rear differential is located in the rear axle housing, usually near the center of the rear axle.
3. Raise the Truck: Securely jack up the rear of the truck and place it on jack stands. Ensure the truck is stable before proceeding.
4. Locate the Drain and Fill Plugs: The drain plug is usually located at the bottom of the differential housing. The fill plug is typically on the top or side of the housing.
5. Remove the Drain Plug: Position your drain pan under the drain plug and carefully loosen and remove the plug using the appropriate wrench. Let the old fluid drain completely. This may take some time. Inspect the old fluid for metal particles or unusual discoloration.
6. Remove the Fill Plug: Loosen and remove the fill plug. This allows air to escape while you add new fluid.
7. Replace the Drain Plug: Once the old fluid has drained, reinstall the drain plug and tighten it to the manufacturer's specified torque (found in your owner's manual). Do NOT overtighten.
8. Add New Fluid: Using a funnel (or pump), carefully add the correct amount of new rear differential fluid. Refer to your owner's manual for the correct capacity. Add fluid until it begins to overflow from the fill hole.
9. Replace the Fill Plug: Once the fluid level is correct, reinstall the fill plug and tighten it to the manufacturer's specified torque.
10. Lower the Truck: Carefully lower the truck from the jack stands.
11. Check for Leaks: Inspect the area around the drain and fill plugs for any leaks.
12. Dispose of Old Fluid Properly: Take the used differential fluid to a recycling center or auto parts store that accepts used oil.
Important Considerations:
* Limited-Slip Differential: If your truck has a limited-slip differential (LSD), you'll need to use the correct type of gear oil formulated for LSDs. Failure to do so can damage your differential. Your owner's manual will specify this.
* Torque Specifications: Always use a torque wrench and tighten the drain and fill plugs to the manufacturer's recommended torque. Over-tightening can strip the threads.
* Fluid Type: Use the exact type and viscosity of gear oil recommended in your owner's manual.
If you are not comfortable performing this task yourself, it's best to take your truck to a qualified mechanic. This is a relatively simple job, but incorrect procedures can lead to damage to your rear differential.
