Combine granulated sugar and 3 tblsp. flour in large bowl. Add peaches and the lemon juice.
Combine brown sugar, ¼ c. flour and pecans in small bowl. Mix in butter until mixture is crumbly. Sprinkle one third of pecan mixture over bottom of pie shell; cover with the peach mixture and sprinkle remaining pecan mixture over peaches.
Bake in hot oven (400°F.) until peaches are tender, about 40 minutes.