Of the Toyota trucks covered, only the 5VZ-FE V6 and 2UZ-FE V8 engines use timing belts. All others use timing chains.
Toyota recommends that the timing belt be replaced at 60,000 miles (96,000 km) on vehicles that are used in extensive idling or low speed driving for long distances. Police, taxi and door-to-door deliveries are commonly used in this manner. This is considered severe service and the timing belt should be replaced every 60,000 miles (96,000 km) in these cases. If your vehicle has high mileage, you may want to consider replacing the belt to prevent the possibility of having it snap. If your engine is being overhauled, inspect the belt for wear and replace if needed. In the event the belt does snap while you are driving, turn the engine OFF immediately. For removal and installation procedures, please refer to the following topic(s): Engine Mechanical, Timing Belt.