Check the oil level. You may not need to replace the oil if there is a sufficient amount. Pull out the oil cap and read the stick. The stick has two holes, and the oil level should be somewhere between them. If it is lower than the first hole, you should replace the oil.
Start the engine and heat up the oil. This is especially important in cold weather, just the kind of weather you will experience during snowblowing season. Heating up the engine will thin out the oil, making it easier to drain.
Place a pan underneath the drainpipe to catch any oil that spills. This will prevent staining in your garage or driveway when you pour your oil into the machine.
Unscrew the drainpipe to let out the old oil. You will find the drainpipe on your Troy-Bilt below the engine on the back side of the snowblower. Let the oil flow out into the pan you placed underneath.
Screw on the drainpipe tightly. You may want to clean the drainpipe with a paper towel after it finishes draining before you screw it back on.
Remove the oil cap. Place the cap and dirty stick on a towel or pan to prevent staining.
Pour the new oil into the tank. Troy-Bilt snowblowers come with a variety of tank sizes. The standard size is less than a quart, so you should read the instruction manual for the exact size of your model. This will tell you how much oil you can pour into the tank without making a mess.
Secure the oil cap tightly after you are finished pouring the oil.