You'll find two hex head plugs facing downward on the main/big tranny pan. The drain plug is the lower of the two that can be easily seen. The fill/level check plug is not so obvious. It's in the rear, right corner of the main pan, at the top of a semi-circle recess stamped deep into the pan. Both plugs are identical is size & dimmension. As with any auto tranny, you have to check ATF level on a level surface, with the vehicle running & fully warmed up. ATF should just dribble out of the fill hole- indicating adequate level. If you check it with the truck off, ATF will POUR out of the hole since much of the ATF drains to the pan when the engine is off. You have to use a pump to get new ATF up & into the tranny.