1999 Chevrolet Express Van Owner's Manual - Page 253

yellowblue 5. Install a new filter element with the folds in the down position. Reverse Steps 1 through 4 to replace the air cleaner. See "Normal Replacement Parts" for the proper filter to use. Refer to the Maintenance Schedule to determine when to replace the air filter and crankcase ventilation filter. See "Scheduled Maintenance Services" in the Index. If the air cleaner/filter is off, a backfire can cause a damaging engine fire. And, dirt can easily get into your engine, which will damage it. Always have the air cleaner/filter in place when you're driving. NOTICE: Automatic Transmission Fluid If your vehicle has a diesel engine, see "Automatic Transmission Fluid" in the Diesel Supplement. CAUTION: Operating the engine with the air cleaner/filter 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 cleaner/filter off. 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's GVWR is over 8,600 or if the vehicle is mainly driven under one or more of these conditions: D In heavy city traffic where the outside temperature regularly reaches 90_F (32_C) or higher. D In hilly or mountainous terrain. D When doing frequent trailer towing. 6-17