An improved method for predicting the remaining useful life of transmission oil and an apparatus for practicing the same are provided. The method includes: detecting if the transmission has completed a new shift; if yes, determining a total shift count; determining accumulated distance and accumulated time parameters; determining a transmission temperature degradation factor; detecting if the lockup clutch is open and if the transmission is in range; if yes, determining a converter degradation factor; determining a total degradation factor based at least in part upon the transmission temperature degradation factor and converter degradation factor; determining an oil life time limit and oil life distance limit; determining if either the accumulated time parameter is greater than the oil life time limit or the accumulated distance parameter is greater than the oil life distance limit; if yes, activating a service indicator to notify vehicle occupants that transmission oil service is required.