If you are not positive that this problem was not there before, read on:
If you have the shift cable disconnected @ the trans and it is still requires excessive effort to move the selector through the ranges, here is what we do: remove the selctor lever from the trans, remove the range sensor (if equipped), remove the linkage seal. Now spray WD-40 in where the seal was and work the shaft through the gear pattern. I really doubt that anything got bent and have done this many times with success. The only thing that you will need is a new linkage seal.
1957 Nash Metropolitan
1960 Bonneville Conv 3x2 1964 Bonneville Vista
1965 Bonneville Conv
1965 2+2 455 3x2 and 1966 421 2+2 3x2 (donor car)
1967 GP Conv