How to Change the Oil in the Rear Axle of C5 Corvette
If your Chevy Corvette makes a clinking or grinding noise from the rear when you turn, you may need to change the oil in the rear axle. This noise is caused by the clutch plates rubbing and slipping. This means that the oil that lubricates them is low or too dirty to work properly. It is recommended that you change the rear axle oil in your C5 every 7,000 miles. Change it as soon as you notice noise coming from the rear axle when you turn.
Drain the Oil from the Axel Case
Drive your Corvette for about ten minutes so the oil can warm slightly. This makes it drain better. You must drive around because the wheels' turning is what will cause the oil to warm. Idling won't do this.
Lift the Corvette up off of the ground. The car must be level while you change the rear axle oil. Back up onto ramps and engage the parking brake. Place large wooden blocks in front of the front tires. Jack up the front of the Corvette using a floor jack. Stabilize the front using jack stands. Place them into the jack notches on the under body directly behind the front tires.
Look on the rear axle for the axle case. You will notice two plugs on the passenger side of the axle case. One is located underneath the case. The other is on the side of the case. The one on the bottom is the drain plug, and the one on top is the fill plug.
Place large piece of cardboard on the ground directly under the axle case plugs. Put a drain pan on top of the cardboard to catch the oil that will drain from the case.
Remove the fill plug. Remember that this is the plug on the side of the case. Use a 10mm Allen wrench to loosen the drain plug. Once it is loose, use a 3/8 swivel arm socket wrench to completely remove it. Some oil may drain out while you are removing the fill plug. Put the plug in a safe place.
Loosen and remove the drain plug in the same way you did with the fill plug. The drain plug is the plug underneath the axle case. When this plug is removed, the oil will flow out of the case freely. Allow all of the oil to drain from the case. This will take at least three hours. Once the flow of oil slows to a trickle, you can continue.
Clean the axle case plugs and the area that each fits into using a clean shop rag. Replace the drain plug. You can do this using a torque wrench, or you can do this by hand using your socket set. If you use a torque wrench, you need to tighten the plug to 26 pounds per foot. If you tighten by hand, you should tighten until the plug is secure. Over tightening can cause the axle case to crack.
Refill the Axel Case With Oil
Add Dextron LS Gear Oil 75W-90 to the fill hole using an after market fill tube that you can buy at your local auto parts store. Screw the connector onto the bottle of oil. Insert the open end of the tube into the fill hole. Squeeze the bottle to get the oil into the axle case. Your Corvette needs about two quarts of oil in the rear axle case. You should have three quarts on hand as it is difficult to get all of the oil out of the bottle. More than likely, you will spill some.
Replace the fill plug once the case is full of oil. You will notice oil dripping out when the case is full. You will have to tighten this plug using your 3/8 swivel arm socket wrench. The torque wrench is too large to fit on the side of the axle case.
Remove the jack stands. Lower the front of the car using the floor jack. Remove the wooden blocks from in front of the tires. Release the parking brake and drive off of the ramps.
Drive your Corvette in eight to ten tight figure eights as soon as possible. This distributes the oil evenly around the system.
Things You Will Need
- Wooden Blocks
- Floor Jack
- Jack Stands
- Drain Pan
- 10mm Allen Wrench
- 3/8 Swivel Arm Socket Wrench
- Shop Rags
- Torque Wrench
- Dextron LS 75W-90
- After Market Fill Tube
- Start draining the oil from the axle case in the evening if possible. Allow it to drain all night. Continue the process the following morning. This allows enough time for all of the oil to drain out of the case.
- On 2005 models, the drain plug is located above a leaf spring. In this case, you will need to use an L-shaped 10mm Allen wrench to loosen the drain plug.
- Don't add any additives, including friction modifier, to the oil. This is no longer recommended because the Dextron LS Gear Oil 75W-90 contains all necessary ingredients.
- Never throw oil away in a trash can or dump it out on the ground as it is illegal to do so. You must take the used oil to an approved recycling or disposal center. You can contact your local waste disposal company to find a location in your area.