My van wouldn't go into park a few weeks ago.  Now it'll shift into
1st gear just fine, as measured by the linkage at the transmission,
but won't shift into any other gear no matter what you do with the
lever.  From playing around with it for a while it appears that 1st
gear is where the linkage cable has been pulled to the maximum, so my
problem is that the cable will pull just fine but won't push back up
into the other gears or park.  If I manually move the shift linkage at
the transmission I can put it into all of the positions, and if I put
it into park I can then easily pull with the shifter on the steering
column into any position.

I'm thinking that maybe the shift linkage at the transmission is
sticking or harder to move, but I just oiled/greased it and that
didn't make a difference.  Also I'm not sure how to get at the linkage
mechanism near the steering colum and would probably have to rip apart
the dash.  I'd like to avoid that if possible.

Any thoughts?