1995 GMC Yukon Owner's Manual - Page 294

While refueling, hang the cap inside the fuel door. To take off the cap, turn it slowly to the left (counterclockwise). Be careful not to spill gasoline. Clean gasoline from painted surfaces as soon as possible. See "Cleaning the Outside of Your Vehicle" in the Index. When you put the cap back on, turn it tothe right until you hear a clicking noise. NOTICE: If you need a new cap, be sure to get the right Your dealer type. can get one for you. you get the wrong type, may not fit or If it have proper venting, and your fuel tank emissions system and might be damaged. 6-12