You must remove the transmission from the vehicle. Start by draining the atf from the transmission. Once the fluid is drained and the transmission is out of the vehicle, remove the transmission oil pan. Inside the pan at the front of the transmission on the passenger side you will see a ciol of wire with ither one or two wires(depending on year) comming out and running across the valve body. This is the control soleniod for the lock-up torque converter. Remove this soleniod by removing the two 8X1.25mm bolts(10mm heads). Once the soleniod is removed, remove the seven 10X1.25mm bolts (13mm heads) located behind the torque converter that fasen the pump housing to the transmission case. Once the bolts are removed, used the GM AT pump puller. If you do not have such puller use a large flat head screw driver inside the tranny pan, you will notice infront of the valve body there is three holes/slots in the case casting were you can see the back of the pump. Use the screw driver to pry at these location. Be carefull to pry the pump ot as striat as possible to prevent jamming. If you have any further questions you can contact me direct at luda8890@yahoo.com