1996 GMC Safari Owner's Manual - Page 250

Refer to the Maintenance Schedule to determine when to replace the air filterand the crankcase ventilation filter. See."Scheduled Ma'--'enance Services" in the Index. Automatic 'TransmissionFluid 'hen to Check and Change A good time to check your automatictransmission fluid level is when the engine oilis changed. air Operating the engine,,with the cleaner off can causeyou or others to be burned. The air cleaner notonly cleans theair, it stops flame if the engine backfires.f it isn't there, and the I engine,backfires,you could be burned. Don't drive withit off, and be careful working on the engine with the cleaner off. air Change both the fluid and filter every 15,000 miles (25 000 km) if the vehicle is mainly driven under one or more of these conditions: 0 In heavy city traffic where the outside temperature regularly reaches 90°F (32 C) or higher. O In hilly or mountainous terrain. 0 0 When doing frequent trailer ,towing. Uses'such as found in taxi, police or delivery service. NOTICE: If the air cleaner is off, a backfire can cause a. damaging enginefire. And, dirt caneasily get into yourengine, which will damage it. Always have theair cleaner in place when you're driving. If you do not use your vehicle under any of these conditions, change the fluid and filter every 30,000 miles (50 000 km). See "Scheduled Maintenance Services" in the Index. 6-20