Combine cake mix, oil, eggs, pudding and water and 1 tsp vanilla. Beat at medium speed for 2 minutes. Pour into a greased and floured 9 x 13 pan. Bake at 350~ for 40-45 minutes or until cake tests done. In a saucepan mix the flour with the milk. Cook until thick, stirring constantly; cool. Add sugar, salt, crisco, margarine and 1 tsp vanilla. Beat until fluffy. Spread on the cooled cake. Store in refrigerator.