I've got a buddy that has a 63 Caddy convertible with an odd tranny problem. First, it's an odd tranny in that the shift detents are P - N - D - L2 - L1 - R, rather than P - R - N - D - L2 - L1. For some odd reason, you can only move the shifter into L2, L1, and R. The lever will not move into the other gears. I've ruled out the linkage and nothing else is obvious. Any tranny guys out there have any ideas? Valve body issues?

 

The tranny should be the Hydramatic Dual Coupling(Chiltons 1954-1963 pg.850).
Without reading the entire service & repair chapter, I would say that there is probably minor damage at least that might include the parking pawl &/or the detent plunger.
No, I'm no tranny expert. Just reading the book.
AL.