I want to cut this rectangle border shape(Picture below) into 4 pieces without affecting the gradient color but cannot figure out how. I have tried pathfinder tool, scissors tool, removing anchors. Does anyone have any idea how?
Copy the object in place four times, and put a different clipping mask on each of the four copies. Voila.
As discussed in comments, this may actually be the only way to accomplish this outcome without manually recreating the gradient.