I am not sure if this matters, but out of curiosity I drove the truck at 55mph for 10-15 minutes, and turned over drive off, forcing the engine to be at a higher RPM(about 3100rpms) than when the over drive is on, and at 70mph (about 2500 rpms). The light did not come on. I do not understand why the light would flash at 70mphs and higher, but not at a higher RPM. I would assume that forcing it to a higher RPM would make it flash the light at a lower speed. Any ideas?