1997 Jaguar XJ6 transmission light

I have only had the 1997 XJ6L for two weeks and when [in cruse control] I came to a hill. As the engine speed increased to climb the hill the trans. Light came on. After checking the fluid level I restarted and every thing was fine. A week later when I was parking and turning the wheel hard the car died. I didn't think much of that, I can understand why this could have happened. The problem came after restarting to go home the transmission light came on and the engine would not up shift out of second gear. After turning the engine off and restarting it ran fine.I hope this isn't a big problem because my daughter just got her license and I just gave my good running car to her. Thanks for any help, Eliot