a few weeks ago I drove ten miles, was at a job for an hour, and when I returned and turned the truck on the warning light was on. I checked the fluid and drove home with it on the whole way. Since then I have driven it around the neighborhood withoutt the light coming on. Today, I returned to the job. When I returned to the truck the light came on, and went out after a half mile. I made four stops, with the same thing happening. It's 60 degrees here and I changed fluid a year ago. Because the light is predictable after a certain distance I feel it is functioning correctly, has this happened to anyone else?