Car goes NEUTRAL!! 2002 Chrysler 300m, 160,000+ miles. Automatic

I need advice from the car gurus out there about
my Chrysler.  When the vehicle is cold, you can
drive it for only a few seconds,  come to a stop,
and it acts like it shifts itself Into neutral.  You can
rev the throttle while in drive or in reverse and all
that happens is the RPMs go up but the car just
sits there. After 30 seconds or so it kicks into gear
again and drives fine. No shifting problems when
working, but I noticed when its having its issue,  
and you shift it into manual mode (The mode with
the + and - ), it starts in 2nd gear and wont shift
down into first gear.

What's going on with the car!!!!