Heat 1 1/2 cups milk and 1 cup butter to 120° to 130° in a medium saucepan; set aside.
Combine 1/2 cup sugar, yeast, salt, and 2 cups flour in a large mixing bowl. Gradually add warm milk mixture, beating at medium speed of an electric mixer 2 minutes. Add eggs, vanilla, and 2 1/2 cups flour; beat 2 minutes. Gradually add remaining flour to make a soft dough (dough should remain soft and slightly sticky).
Turn dough out onto a lightly floured surface; knead 5 minutes or until smooth and elastic. Cover; let rest 10 minutes.
Shape dough into a ball; place in a well-greased bowl, turning to grease top. Cover and let rise in a warm place (85°), free from drafts, 1 1/2 hours or until doubled in bulk.
Punch dough down; turn out onto a lightly floured surface. Divide into three equal portions, and set aside 2 portions. Roll one portion dough into a 21- x 7-inch rectangle on a lightly floured surface. Melt 2 tablespoons butter, and brush evenly over dough, leaving a 1- inch margin. Combine remaining sugar and cinnamon, stirring well to blend; sprinkle 1/3 cup sugar mixture over dough. Sprinkle 1/2 cup raisins and 1/2 cup pecans evenly over dough, leaving a 1-inch margi
Roll up dough jellyroll fashion, beginning at long side; pinch edges to seal. Place roll on a large, greased baking sheet, seam side down; shape into a ring, and pinch ends together to seal. Repeat procedure with each dough portion.
Make cuts in dough with kitchen shears at 1-inch intervals around ring, cutting two-thirds of the way through roll with each cut. Gently turn each piece of dough on its side, slightly overlapping slices. Repeat procedure for each dough portion
Cover and let rings rise in a warm place (85°), free from drafts, 30 minutes or until doubled in bulk. Bake at 375° for 20 minutes or until golden brown. Transfer to a wire rack.
Combine powdered sugar and 1/2 cup milk; drizzle over rings. Slice and serve warm.
Note: Tea rings freeze well; thaw and heat quickly.