I have a 2000 Dakota 4x4 with the 4.7L V8 Magnum with automatic
trans.  I ran over a pothole the other day and the Transmission
indicator went nutty, outlining all gears instead of just drive.
Also, the check engine light came on and the transmission seemed to
hiccup every few seconds giving a slight hesitation.  The transmission
indicator has since returned to normal and the slight hesitation gone
away, however, at highway speeds there is a more pronounced hiccup
which feels almost like someone threw a stick in the gears (a quick
hesitation and noticeable bump).  This tends to occur after I run over
a bump in the road,  but occasionally will occur randomly every 10
minutes or so.  I took it to a repair shop but he was clueless.  He
said there were two codes from the transmission, but he didn't know
what they mean.  Also, there was nothing structurally wrong with my
truck.  I have had similar symptoms before and it turned out to be the
speed sensor in the rear diff (even though the speedometer still
worked).  There is also a code from the A/C compressor.  The mechanic
said that the compressor was switching on and off due to low freon and
the idle was going up and down as the compressor turned on and off.  I
had the freon filled a while ago, and it didn't work out too well.
The guy at Jiffy Lube said the air temperature went up and the
compressor started smoking so he removed the freon.  Haven't dealt
with the A/C in over a year but the code from the A/C is new and could
have started when I hit the pothole. Any thoughts?

Here are the codes and what I believe they mean:

T0645- A/C Clutch relay circuit problem
T1690- no message received from electronic transmission control module
or the Aisin transmission
P1739- Slip Solenoid System