2003 GMC Envoy Owner's Manual - Page 316

To check or replace the engine air cleaner/filter, do the following: 1. Remove the three screws on the engine air cleaner/filter and lift off the cover. Automatic Transmission Fluid When to Check and Change A good time to check your automatic transmission fluid level is when the engine oil is changed. Change both the fluid and filter every 50,000 miles (83 000 km) if the vehicle is mainly driven under one or more of these conditions: 0 2. Twist out the old engine air cleaner/filter and replace it with a new one, if needed. 3. Reinstall the cover. In heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher. In hilly or mountainous terrain. When doing frequent trailer towing. Uses such as found in taxi, police or delivery service. Operating the -..gine with the air clear._.Ifilter off can cause you or others to be burned. The air cleaner not only cleans the air, it stops flame if the engine backfires. If it isn't there and the engine backfires, you could be burned. Don't drive with it off, and be careful working on the engine with the air cleanedfilter off. Notice: If the air cleaner/filter isoff, a backfire can cause a damaging engine fire. And, dirt can easily get into yourengine, which will damage Always have it. the air cleaner/filter in place when you're driving. If you do not use your vehicle under any of these conditions, change the fluid and filter every 100,000 miles (166 000 km). 5-21