1. Gather Supplies:
* New Differential Fluid: Check your owner's manual for the correct type and amount. Common types are 75W-90, 75W-140, or synthetic equivalents. The quantity needed depends on your specific differential (look up your axle code to be sure). Don't guess; an incorrect type or quantity can damage your differential.
* New Differential Cover Gasket (or RTV sealant): A new gasket ensures a proper seal to prevent leaks. Some use RTV sealant instead, but follow the instructions carefully if you opt for this.
* Drain Pan: Large enough to hold the old fluid.
* Wrench(es): The correct size to remove the drain and fill plugs. This will likely be a 10mm or 11mm for the fill plug and a 10mm, 11mm or 12mm for the drain plug.
* Torque Wrench: Essential to tighten the fill plug to the correct specification (check your owner's manual). Overtightening can strip the threads.
* Jack and Jack Stands: Safely lift the truck. Never work under a vehicle supported only by a jack.
* Wheel Chocks: To secure the front wheels.
* Gloves: To protect your hands from the old, dirty fluid.
* Funnel: To help pour the new fluid.
* Rags or Shop Towels: To clean up any spills.
2. Safety First:
* Park the truck on a level surface, engage the parking brake, and chock the front wheels.
* Allow the differential to cool down before starting. Hot fluid can cause burns.
3. Procedure:
* Jack up the rear end of the truck and securely support it with jack stands.
* Locate the drain plug and fill plug on the differential cover. The drain plug is usually at the bottom.
* Place the drain pan under the drain plug.
* Carefully remove the drain plug. Let the old fluid drain completely. This may take some time.
* Once drained, replace the drain plug and tighten it to the manufacturer's specification (consult your owner's manual). Don't overtighten!
* Clean the differential cover thoroughly around the fill plug area.
* Remove the old gasket (if using a gasket). If using RTV, clean off the old sealant.
* Install the new gasket (if applicable) or apply a bead of RTV sealant to the differential cover following the manufacturer's instructions.
* Carefully reinstall the differential cover.
* Locate the fill plug.
* Using a funnel, pour in the correct amount of new differential fluid. Refer to your owner's manual for the exact capacity. It's often best to slightly underfill, then check the fill level.
* Replace the fill plug and tighten it to the manufacturer's specified torque using a torque wrench. Overtightening can strip the threads.
* Lower the truck.
* Check for leaks around the drain and fill plugs and the differential cover.
* Run the truck for a few minutes to circulate the new fluid. Then, recheck for leaks.
Important Considerations:
* Axle Code: Your truck's axle code (found on a sticker under the hood or in the glovebox) determines the specific type and amount of fluid needed. Look this up online to be certain.
* Owner's Manual: Always consult your owner's manual for specific instructions and torque specifications for your vehicle.
* Professional Help: If you're unsure about any part of this process, it's best to take your truck to a qualified mechanic. Improperly servicing your differential can lead to serious damage.
This is a general guide. Always prioritize safety and refer to your vehicle's specific service manual for the most accurate information.
