the other i was changing my oil and and lubing the front end when i looked behind the drivers side wheel well and noticed that there was a sensor in the tranny that the wires had been disconnected.  my car throws no codes and seems to run fine but i was just curious what sensor this was.  thanks for the help 
by the way the car is an 03 ecotec w/ the getrag 5 speed
ecopower
 
if the sensor has a white connector on it..  its the reverse light switch...  
 
 
here i dug up a picture of my tranny before we put it in...  and it circled what i am talking about..  if this is what your talking about its the Reverse light switch.
 
 
 
thanks that's definetly what it is. i'll have to pick one and put it in. 
ecopower