After jacking the 1993 LS400 up to do a fuel filter the gear selector moves freely but doesn't engage gears properly .Doesn't go into park ,so key can be removed.Moves into drive but is actually in neutral. Could the problem be a bad shifter cable that just happened to go bad?

no shifter cables, it's a conventional rwd car. You may have a bent/broken shifter mechanism or shift linkage, but you'd have had to abuse it to have that happen.

You're saying the shifter is connected directly to the trans? I haven't looked under there yet as a buddy will sell me the car cheap.