[kaiser]

It sounds as if the gear change is not adjusted correctly.
If the car does not start in N or P, the lever is not correctly adjusted to trigger the inhibitor switch.
If they have adjusted that right, it is still possible that the gear selector on the box is not adjusted correctly to go into top and OD. If almost there, the box will tend to hunt as if it will try and shift, but it will be reluctant to do so.

There is an adjustable rod from the lever on the shift box to the gearbox, running under the shifting console.