Adjust an oven rack to the middle position and preheat oven to 325 degrees. Grease a 12-cup Bundt pan well with butter.
In a large bowl add the yellow cake mix, eggs, vegetable oil, lemon pudding mix, and 7UP. Stir well to combine.
Pour the batter into prepared pan and bake until a toothpick inserted in the middle of the cake comes out clean with a few crumbs attached, about 45 to 55 minutes.
Remove from the oven and cool completely in the pan on a wire rack. Remove cake from the Bundt pan.
To make the glaze, in a medium bowl, whisk together the powdered sugar, lemon juice, lime juice, 7UP, and zest. Drizzle over the cooled cake.
