Here's a general outline. This is NOT a substitute for a detailed repair manual specific to your vehicle. If you're uncomfortable performing these tasks, take your truck to a qualified mechanic.
Tools You'll Need:
* Jack and jack stands: Essential for safely working under the truck.
* Wheel chocks: To prevent the truck from rolling.
* Wrench(es): The size(s) will depend on your specific transfer case and differential drain and fill plugs. Likely 10mm, 13mm, or 15mm. A socket wrench set will be most helpful.
* Drain pans: To catch the old fluid.
* Funnel: For refilling.
* Torque wrench: Extremely important to tighten drain and fill plugs to the correct specification to prevent leaks. Your owner's manual will list the appropriate torque values.
* New transfer case fluid: Use the type and amount specified in your owner's manual (often a synthetic ATF).
* New differential fluid: Use the correct type and amount specified in your owner's manual (likely a 75W-90 or 75W-140 gear oil; look for a limited-slip additive if your differentials have that feature).
* Gloves: To protect your hands.
* Rags or shop towels: For cleanup.
* Metric Socket Set: This will be your best friend
* Pry bar or similar tool (optional): For stubborn drain plugs.
Procedure:
1. Safety First!
* Park the truck on a level surface, engage the parking brake, and chock the wheels.
* Wear safety glasses and gloves.
2. Transfer Case Fluid Change:
* Locate the Transfer Case: Usually found towards the rear of the transmission.
* Drain: Position a drain pan under the transfer case drain plug. Carefully loosen and remove the plug, allowing the old fluid to drain completely. It might be hot, so be cautious.
* Refill: Once drained, reinstall the drain plug. Locate the transfer case fill plug (often higher on the case). Using a funnel, add the correct amount of new transfer case fluid as specified in your owner's manual. You may need a pump to add the fluid.
* Check the Level: Many transfer cases don't have dipsticks. You may have to add fluid until it starts to come out of the fill hole. Refer to your manual for the correct method.
3. Differential Fluid Change (Front and Rear):
* Locate the Differentials: The front differential is near the front axle, and the rear differential is near the rear axle.
* Drain (Front and Rear): Position a drain pan under each differential's drain plug. Loosen and remove the plugs carefully, allowing the old fluid to drain completely.
* Remove Cover (Optional): For a more thorough cleaning, you can often remove the differential cover. This requires additional tools and care to avoid damaging the gasket. This step is more advanced.
* Refill (Front and Rear): Once drained, reinstall the drain plugs. Locate the differential fill plugs (often near the top of the differential). Using a funnel, add the correct amount of new differential fluid as specified in your owner's manual. Again, you'll likely use a pump. You want to fill to the bottom of the fill hole.
* Reinstall Cover (Optional): If you removed the cover, reinstall it with a new gasket and torque the bolts to the manufacturer's specifications.
* Check the Level (If Possible): Some differentials have a fill plug that serves as a level indicator. Add fluid until it trickles out.
4. Torque Specifications:
* Extremely important: Use a torque wrench to tighten all drain and fill plugs to the manufacturer's specifications. This is crucial to prevent leaks. Find these specs in your owner's manual or a repair manual.
5. Cleanup:
* Dispose of the old fluid properly according to local regulations.
Important Considerations:
* Limited-Slip Differentials: If your truck has limited-slip differentials, make sure to use the correct type of fluid for them. Incorrect fluid can damage the limited-slip components.
* Manual vs. Automatic Transfer Case: The procedure might vary slightly depending on the type of transfer case your truck has.
* Repair Manuals: Consider investing in a factory service manual or a Haynes/Chilton repair manual specific to your 2002 Chevy Silverado 6.0L. These manuals provide detailed diagrams and instructions.
This is a general guide; always consult your owner's manual and/or a repair manual for specific instructions and torque specifications for your vehicle. If you are unsure about any step, seek professional help. Incorrect fluid levels or over-tightening can cause serious damage.
