Sauté diced pears in butter over medium high heat. When slightly brown around edges, add sugar and cinnamon and continue to cook until lightly translucent. Set aside to cool.
Combine all-purpose and whole wheat flour, brown sugar, butter and salt in bowl of mixer until it resembles coarse meal. Set 8 cups.
Whisk pumpkin, sour cream, sugar, spices and baking soda together and add to bowl of mixer. Beat until fully incorporated.
Add eggs slowly, mixing well to combine each addition before adding the next.
Divide batter between 3 well-greased hotel pans. Evenly distribute caramelized diced pears over the top in a single layer and cover with reserved crumble.
Bake in a 350 degree oven until lightly golden brown and the edges begin pulling away from the sides of the pan. Cool on a rack before cutting.