03-72LE 4-Speed Automatic Transmission

Check fluid at regular intervals. Noticing a change in color, odor or fluid level can serve as a warning of possible transmission problems.
To check fluid level, bring fluid to operating temperature of 200°F. With vehicle on a level surface and engine idling in Park and parking brake applied, the level on the dipstick should be at the Full mark. To bring the fluid level from the Add mark to the Full mark requires one pint of fluid. If additional fluid is required, use only Dexron II or Dexron IIE automatic transmission fluid.
When adding fluid, do not overfill, as foaming and loss of fluid through the vent may occur as the fluid heats up. Also, if fluid level is too low, complete loss of drive may occur especially when cold, which can cause transmission failure. The oil should be drained, the oil pan removed, the screen cleaned and fresh fluid added every 30,000 miles for trucks under 8600 lbs. GVWR or every 24,000 miles for vehicles over 8600 GVWR. For vehicles subjected to more severe use such as heavy city traffic especially in hot weather, prolonged periods of idling or as a tow vehicle this maintenance should be performed every 15,000 miles for trucks under 8600 GVWR, or every 12,000 miles for trucks over 8600 GVWR.