To service the 40TE torque converter, detach the transmission and torque converter, let the converter housing drain onto the pan and place the pan under the housing end. You must confirm that the transmission is secure on either the lifting device or the work surface, as taking away the torque converter can make the vehicle unstable because its center of gravity will shift. It's important to pull the torque converter free from the transmission after the center hub is no longer in contact with the oil pump seal. Before mounting the converter hub, examine it and the drive notches for edges, scratches or dents and if they are present, polish them with 320/400 grit paper or crocus cloth to keep the pump safe. Apply transmission fluid to the converter hub and to the edge of the oil pump seal, then place the converter into its slot in the transmission without damaging anything. Lay the torque converter over the oil pump seal opening, fit the hub into the oil pump and while rotating the converter inward, push it all the way to the oil pump gears. To test the converter's seating, use a scale and straightedge, ensuring it is pushed far enough back onto the converter lugs for a 1/2 inch space to appear behind the straightedge. When it is safer to support the converter from another angle, secure it with a C-clamp fixed to the housing, install the transmission and complete the process with the suitable fluid.