I was wondering how many quarts a C6 will take if you just drain and fill the pan? i have the shallow pan

 

My C6 takes 13 quarts total. Buy a case of ATF (12 quarts). Add about 7 or 8 quarts, start it up, move the selector through all the gears, then give it some time to warm up, and check the level. Add in half quart intervals until it is full. Make sure you are checking the level with it warmed up a bit and idling in park on a level surface. After your first drive, check the level and make sure it is full. Do not overfill. Good luck.