Replacing the Differential Fluid in the C5 Corvette

This was easier than I expected, and I saved a bunch of Cash doing it myself.
Don't be scared to do this yourself. Its a piece of cake!

My 2004 Z06 (7yrs old - 19K miles) had never had this fluid changed before.

What I got to perform this job:

1.) Amsoil - SEVERE GEARŪ Synthetic Extreme Pressure (EP) Lubricant 75W-90 (SVG) (Need 2x Quarts)

2.) Amsoil - Slip-Lock™ Differential Additive (ADA)

3.) Amsoil - Hand Pump

Thanks to Corvette Forum Member "Subdriver" for hooking me up as a Amsoil prefered member and a good discount !

Be sure to have various tools on hand.
Specifically a 10mm Allen socket, Torque wrench designed for 20 ft lbs, an oil drain container, and teflon tape can't hurt.
I also advise having some Simple Green for degreasing fluid spills, and Shop Towels for wiping up any mess made.

Put your car on Ramps, and ensure that the frame of the car is as "LEVEL" as you can get it. This is important.
The "FULL" level of the differential depends on the car being level.

This is the differenetial "FILL" plug. Viewed from the back of the car.

This is the differenetial "Drain" plug. Viewed from under the differential itself.

Some say to drive the car a while to let the fluid heat up before draining the differential
I did not do this, and the fluid poured out like water... Either way is fine I guess.

Be sure to remove the "FILL" plug first. Mine had never been off and was a bit stiff to break free
You don't want to drain your fluid and find that you can't remove the FILL plug later.

"FILL" plug removed. I could feel fluid inside the hole with my pinkey finger. It was still full.
Clean all dirt from around the FILL hole

Place the oil drain container under the DRAIN plug location of the differential
Remove the DRAIN plug of the differential
It's going to pour out very quickly. Be ready for this.
This is where the Shop Towels, and Simple Green come in handy. 8-)
I hope you have a strong stomoch, because the differential oil STINKS !!!

Clean both the FILL and DRAIN plugs. I put a couple turns of teflon tape around both for a little more security.
Clean the area around the DRAIN plug. Reinsert the DRAIN plug, and torque to 20ft lbs (as per GM manual).
Install the Amsoil hand pump into the Amsoil 75w-90 quart of oil.

Insert the end of the plastic tube an inch or so inside the FILL hole.
Pump the hand pump slowly until the first quart is empty.
I added about 1/2 of the Amsoil Slip-Lock at this time. Just squirt a bit in the the FILL hole.

Pour the remains of the first quart into the second quart.
Insert the hand pump into the second quart.
Place a shop towel directly under the FILL hole to catch liquid pouring out.
Slowely pump the second quart into the differntial.
Once you start to notice some pouring out of the FILL hole then your FULL !
I only managed to get about 70% of the second quart into the differential before it leaked out.
I let it settle about 20 mins to debubble. It took a couple more pumps and it leaked out again.
Insert the FILL plug, and tighten to 20ft lbs (as per GM manual)

IMPORTANT GM recomendations after the rear differential fluid has been changed
GM recommends NOT to drive your car at Wide Open Throttle for 300 miles
GM says that it will cause rear end gear noise/whine.
GM recommends you to go to an empty parking lot and do multiple figure 8's to work the new oil into the diferential clutch packs.

Enjoy your fresh oil change in your differntial...!