Forgot to mention that, running the trim to both ends of travel as part of the preflight is a smart move for two reasons, check indication
and that there are no restrictions.
Trim is a "control", full and free it needs to be.
While I'm at it the Navajo elevator system has a "bob weight" attached at the working end.
It is there to correct a pitch stability problem they didn't get right at the original design stage and it got worse when it was stretched to a Chieftain.
It is why the the controls generally flop to the full down position, or they feel "loaded" when you pull back when the aircraft is stationary. That is normal and part of the damping effect.
Its fairly well attached but given the age and serviceability of the average type nowadays it is something you need to watch out for. If it has or does become detached expect some lively flying characteristics, it will not necessarily be uncontrollable, but if you are overweight or at the extreme ends of the C of G envelope who knows, nobody else does either.