Those who own GMC pickup trucks need to make sure that they change the oil frequently. This should ideally be done every three thousand miles. It is possible to wait longer than that if you have no choice. The truck is not going to die as soon as you pass that mark. However, running it for a lot longer can do some real harm to the engine. This damage can last for the life of the vehicle. The best way to take care of a truck, to make sure that you get the most miles possible out of it, is to change the oil when you are supposed to do so. If you do not want to pay to have this done, it is probably something that you can do on your own. The first step is to jack the truck up in the front. A handheld jack should be good enough. After you get it in the air, brace it with some pieces of wood or some other solid material to make sure that it does not fall. You can then climb under it, armed with a wrench and a pan to catch the old oil. Next, you need to locate the bolt that plugs the drain. This should not be hard to do, but it is different for every truck. Once you find it, put the pan under it and take it out. The black oil will pour out of the drain and into the pan. You can then move on to the next step while you wait for it to finish draining. This step is to replace the oil filter. Make sure that you have the right type of replacement filter. You can then unscrew the old one and screw the new one into place. With this done, you just need to put the plug back into the drain. Take the pan out from under the truck and then refill the oil from the top of the engine like you normally would. Many GMC pickup trucks take 30-weight oil, but you should consult the manual to make sure that you use the right type.