1998 Pontiac Firebird Owner's Manual - Page 273

Automatic Transmission Fluid When to Check and Change A good time tocheck your automatic transmission fluid level is when the engine oil is changed. Change both the fluid and every 15,000 miles filter (25 000 km) if the vehicleis mainly driven under one or moreof these conditions: 0 In heavy city traffic where the outsidetemperature regularly reaches90°F (32°C) or higher. In hilly or mountainous terrain. Uses such as high performance operation. When doing frequent trailer towing. If you have the5.7LV8 engine (with the WS6 option), your air cleaner will be located over the radiator near the Uses such as found in taxi, police or delivery service. 0 front of the engine. If you do not use your vehicle under any of these To remove the filter, removethe screws (locatedon the conditions, change the fluid and every filter rear edgeof the air cleaner), the air cleaner and lift 50,000 miles (83 000 km). remove the filter. See "Scheduled Maintenance Services" the Index. in 6-20