How to Remove a 350 Transmission From a GM Truck

1). Raise and support the truck on jack stands. Drain the transmission fluid by loosening the pan bolts with a 13 mm socket and ratchet.
2). Unbolt and remove the driveshaft. Take the four side bolts and the two lower bolts out of the lower torque converter cover to remove the cover.
3). Remove the torque converter bolts using a 15 mm socket and ratchet.
4). Remove the gear shift from the shifter arm on the transmission. If it is a column shift, use an appropriate wrench to remove the nut on the shifter arm. If it is a floor shift, unbolt and remove the bracket attached to the transmission pan. Unbolt and remove the gear shift cover inside the vehicle, then unbolt and remove the shifter arm.
5). Remove the speedometer cable or electrical connector, depending on whether it is cable driven or sensor operated. If cable driven, unscrew the cable end cap at the transmission with the fingers. If there is an electrical connector, unplug the connector.
6). Remove the dipstick filler tube by unbolting the bolt holding it to the transmission bell housing. Twist the tube and lift up. If it is being difficult, use a common screwdriver at the base to pry it up.
7). Place the floor jack under the transmission oil pan and raise it just enough to start to support the weight of the transmission. Unbolt the two transmission mount bolts with a socket and ratchet.
8). Unbolt the bolts and nuts on both sides of the cross member where they are held to the frame. Raise the transmission with the floor jack and remove the cross member from under the rear of the transmission.
9). Lower the transmission enough to gain access to the transmission cooler lines on the passenger side of the transmission. Use a wrench to remove these two lines.
10

Remove all of the transmission bellhousing bolts holding the transmission to the engine. Use a socket with a swivel and a long extension. Make sure the transmission is situated correctly on the floor jack so it doesn't fall off when you pull back on it. Remove the transmission by pulling rearward on it.