1. Preparation:
* Safety First: Jack up the rear of the Suburban securely using jack stands. Never work under a vehicle supported only by a jack. Wear safety glasses.
* Gather Supplies: You'll need the correct type and amount of rear differential fluid (check your owner's manual), a drain pan, a wrench (size will depend on your vehicle, check your manual), a funnel, and rags or shop towels. Consider using gloves as well.
2. Locating the Fill and Drain Plugs:
* Locate the Differential: The rear differential is typically located towards the rear of the vehicle, between the rear wheels.
* Identify the Plugs: The differential usually has two plugs: a lower drain plug and an upper fill plug. They are usually square or hex-head bolts. The fill plug is typically higher than the drain plug.
3. Draining the Old Fluid:
* Position the Drain Pan: Place the drain pan under the drain plug.
* Remove the Drain Plug: Carefully loosen and remove the drain plug using the appropriate wrench. The old fluid will drain into the pan. Be cautious as it will be hot if the vehicle has been recently driven.
* Allow to Drain Completely: Let the fluid drain completely; this might take 15-20 minutes.
4. Replacing the Drain Plug:
* Clean the Drain Plug: Clean any dirt or debris off the drain plug.
* Reinstall the Drain Plug: Tighten the drain plug securely using the wrench, but avoid over-tightening.
5. Adding New Fluid:
* Locate the Fill Plug: Locate the fill plug.
* Remove the Fill Plug: Carefully remove the fill plug.
* Add New Fluid: Use a funnel to add the correct type and amount of differential fluid (refer to your owner's manual). Add fluid until it starts to come out of the fill hole.
* Replace the Fill Plug: Replace the fill plug securely, but again, avoid over-tightening.
6. Lower the Vehicle and Check:
* Lower the Vehicle: Carefully lower the Suburban using the jack stands.
* Check for Leaks: Inspect the area around the drain and fill plugs for any leaks.
Important Considerations:
* Fluid Type: The type of fluid required (e.g., 75W-90, 75W-140) is critical. Using the incorrect type can severely damage your differential. Check your owner's manual.
* Amount of Fluid: The correct amount of fluid is also vital. Overfilling or underfilling can cause problems. Check your owner's manual.
* Differential Condition: If the old fluid is very dirty, dark, or contains metal particles, consider having the differential inspected by a mechanic for potential damage.
If you are not comfortable performing this task yourself, it's best to take your Suburban to a qualified mechanic. Improperly servicing the differential can lead to costly repairs.
