Using a 1/2-to-2-ton floor jack, lift the front of the truck and place jack stands under the frame. Once the truck is lifted enough for you to safely move around under it, begin removing the four bolts connecting the U-joint between the drive shaft and the rear axle. When you pull the drive shaft out of the tail shaft, transmission fluid will pour out of the tail shaft, so place a drip pan or oil-changing pan under the tail shaft of the transmission.
Lines And Linkage
If the truck is an automatic, you will need to remove two transmission lines from the passenger side of the transmission by the bell housing close to the transmission dip stick. If it's a manual transmission you won't have those lines, but you will have shifting linkage on the driver's side of the transmission. Depending on the year of the truck, the linkage is held on by either a cotter pin or locking-sleeve washer. You will also need to remove the speedometer cable. If it's an older truck, it will be a hard-cased cable similar to the emergency brake cable that threads onto the driver side of the transmission just before the bell housing. If the truck is a newer model, it will be an electrical set of wires attached to a plug on the tail shaft.
Remove From Engine
Remove the transmission mount bolt that holds the tail end of the transmission to the cross member on the frame. You will need to either use wood blocks or a jack to support the weight of the transmission. Take out the nine bolts on the bell housing that attach the transmission to the engine--there is one on the top center of the bell housing, two along each side of the bell housing and two on each side at the bottom next to the guide pins.
Remove From Vehicle
Once removed, maneuver the transmission to the rear of the truck about 6 inches until it clears either the clutch kit of a manual or the torque converter of an automatic. When the transmission is free, lower the bell housing end of the transmission down until the tail shaft is clear of the cross member.
If you need to remove the transmission from your Chevy truck, you can do so with the right equipment and tools. You should also refer to your owner's manual. If you don't have an owners manual you can find one at an auto parts store. You will need a floor jack to lift the truck and two jack stands to place under it to safely hold it up while you work. Your tools will be a wrench and socket set and a drip pan to catch old transmission fluid.