ohhh! i missed that you had an aftermarket shift handle.. if its the RAZO style with a vertical button, that probably is your problem, when I installed mine it took 3-4 days worth of tiny adjustments to get the height right to stop rattling but release far enough to get the key back out

after reading your first post again, you may need to take the center console out for the repair. There is a wedge shaped white plastic piece thats slotted to allow the shifter to be locked in place, i believe that it also is connected to the neutral selector (transmission mode) switch. mine popped off once when i had a box fall on the shift handle and force it out of gear