518 short shifts and no od

Line pressure is easy to chk, and it's easy to fix if he halfway knows what he's doing.
Low line pressure can cause a no shift (as in a major internal hydraulic leak)

I would think the shifter may be WAY off and you are not actually in 1st but manual second.
This would be pretty obvious though when you go to park and it won't travel that far.
It almost sounds like it has the wrong manual valve in it.

Maybe Tracy, Fishy68 has an idea?