My house is an "L" shape where the short leg of the "L" is the garage. Above the garage ceiling, the trusses transition from one orientation 90 degrees to another orientation. The different orientations of trusses are different heights above the floor.
This means one-third of the ceiling has the bottom edge of the trusses 1/2-inch lower than the other two-thirds.
When the ceiling drywall was originally installed, the drywall was butted up at this uneven transition and caulked. This joint has failed over time, and then wind blows through the joint (when the garage door is open) making the problem even worse.
What is the proper way to fix this situation?