The 1991 Pontiac Grand Am radiator drain plug can be found on the bottom of the radiator. The radiator drain plug will be in the center of the radiator bottom.
on the radiator
The transmission does not have a drain plug. You have to remove the oil pan to drain.
On the oil pan.
It is on the bottom of the radiator on the drivers side.
Most vehicles do not.
Botom of the engine on the oil pan.
Should be at the bottom of the radiator logically...
There is no drain plug assuming it is an automatic transmission it is drained when removing the transmission pan and changing the transmission filter.
If it does not have a drain plug, just simply remove the lower radiator hose.
there may not be one if there is it is on the bottom if not you just remove the bottom radiator hose to drain