I think my tranny is toast.
You sure that isn't a reverse manual vavle body?
D would be 1st gear
S would be 2nd gear
L would be 3rd gear
But you say 1st gear is in both D and L ?
Why not start in D and get on it kind of hard..2/3 the gas and shift at 5,000+ and run though the gears...you know for sure at 70+mph shifting in to L if that is 1st gear or 3rd gear, lol