Tools You'll Need:
* New differential fluid: Consult your owner's manual for the correct type and quantity. Commonly, it's 75W-90 gear oil, but some may require synthetic or a specific additive.
* Drain pan: Large enough to hold at least 3 quarts of fluid.
* Wrench: The correct size to remove the drain plug (likely a 10mm or 11mm, but verify).
* Wrench: The correct size to remove the fill plug (often the same size as the drain plug, but again, verify).
* Funnel: To avoid spills while refilling.
* Jack and jack stands: Essential for safe working conditions. Never work under a vehicle supported only by a jack.
* Torque wrench (optional but recommended): To tighten the drain and fill plugs to the correct specification (check your owner's manual).
* Gloves: To keep your hands clean.
* Rags or shop towels: For cleaning up spills.
Procedure:
1. Safety First: Park your S10 on a level surface, engage the parking brake, and chock the rear wheels. Use jack stands to securely lift the front end of the vehicle. Never work under a vehicle supported only by a jack.
2. Locate the Differential: The front differential is located at the front of the vehicle, between the front wheels, near the transfer case.
3. Locate the Drain and Fill Plugs: The drain plug is typically located at the bottom of the differential housing. The fill plug is usually on the side or top of the housing.
4. Drain the Old Fluid: Place your drain pan under the drain plug. Carefully remove the drain plug using the appropriate wrench. Let the old fluid drain completely. This may take 15-30 minutes. Inspect the fluid for metal shavings or unusual discoloration; this could indicate a problem.
5. Remove the Fill Plug (Optional but Recommended): Before you replace the drain plug, it’s a good idea to remove the fill plug to ensure it's not seized. This allows for easier filling later.
6. Replace the Drain Plug: Once the old fluid has completely drained, replace the drain plug and tighten it securely using the correct wrench. If using a torque wrench, consult your owner's manual for the specified torque value.
7. Refill with New Fluid: Using a funnel, carefully pour the correct amount of new differential fluid into the fill plug hole. Refer to your owner's manual for the exact capacity. It's usually around 2-3 quarts.
8. Check the Fluid Level: Once you've added the fluid, replace the fill plug. The fluid level should be just below the bottom of the fill hole. If the fluid level is low, add more until it reaches the correct level. If it’s difficult to see the level, remove the fill plug to check.
9. Lower the Vehicle: Carefully lower your S10 using the jack stands. Once the vehicle is on the ground, check for any leaks around the drain and fill plugs.
10. Test Drive: After the fluid change, go for a short test drive to ensure everything is working correctly.
Important Notes:
* Consult your owner's manual: This guide provides general information. Always consult your owner's manual for specific instructions and torque specifications for your 1999 Chevy S10 Blazer.
* Fluid type: Use the exact type and weight of differential fluid specified in your owner's manual. Using the wrong fluid can damage your differential.
* Safety: Always prioritize safety. If you're uncomfortable performing this task yourself, take your vehicle to a qualified mechanic.
This process is a guideline. Variations may exist depending on the exact model and condition of your vehicle. If you encounter any unexpected issues, consult a repair manual specific to your S10.
