Do you have to remove the engine to replace freeze plug on a 1982 GMC diesel stepside pickup 1600 Sierra 6.2 liter 350 8-cylinder engine?

There are freeze plugs in the side of the block, the heads and in the back of the block between the motor and transmission. If it is one of the ones on the back of the block, either the engine or transmission has to be removed to get to them.