Preheat oven to 350°F (175°C).
Prepare the yellow cake mix according to the package directions, using the pineapple juice instead of water.
Fold in the crushed pineapple.
Pour the batter into a greased 9x13-inch baking pan.
Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool completely.
Spread the instant vanilla pudding evenly over the cooled cake.
Top with whipped topping and sprinkle with chopped pecans.
Chill before serving.