Service Intervals
NOTE:
There are 2 Light Duty truck emission control standards classifications: Light Duty and Heavy Duty. Light Duty refers to vehicles up to 8500 lbs. (GVW); Heavy Duty refers to vehicles over 8500 lbs. (GVW).
On "S" models with 4-speed transmission, change transmission fluid after the first 7500 miles and at 30,000 mile intervals thereafter. On all other Light Duty vehicles, check transmission fluid every 12 months or 7500 miles. On Heavy Duty vehicles, check fluid level every 12 months or 6000 miles. Periodic draining and refilling is not required.