Transmition

Hello , i hava a 2003 cadillac deville.. I was on my
way back from work when my cadillac started
smooking and showed on the dash service
transmition. After that a lil wile the car stoped
runny like i would rum but realy slow less then 5
mph or it will stay put and just accelerate but wont
move.. I decided to move it out of the street to a
parking spot where i looked under the car there
was Transmition oil everywhere... I looked under
the car to see what may have happen and i see this
shown in the pictures.. Is on the drivers side by the
front tire.. If you guys know anything please le me
know or what this part is called??...  Also the dip
stick for the trani was dry.. No oil at all..  Please
help.