My 300SD which now has 130K miles on it, has a transmission issue
which is beginning to show.   When the car hasn't been driven for
several days, when I first go to drive it, it takes maybe 10 seconds
of applying some throttle before the car starts to move.  Then it just
slowly starts to move, no lurching, or noise.   After that initial
start, as long as I use it within maybe 2 days, it starts out
normally.     I think it may happen more on a slight grade.  My guess
is that fluid is somehow draining out of maybe the torque converter
and it then needs to refill?  It's been doing this for a year or so
now.  No other symptoms, other than MPG seems to have slipped from the
usual 26MPG down to about 22MPG.   Don't know that there is any
relation though.  It still has the original injectors and was planning
on replacing them soon, as I think that is the most likely MPG issue.
Fluid level is normal and was changed around 100K

I have no problem living with the tranny thing  Just wondering if
anyone has any insight into what it is, will it just remain like this
for a long time with no harm, or is it a sign of impending failure,
better to address it now, etc?

TIA