I have a truck that I purchased in 2004 and have used progressively more and more for business. This year, it will be used about 95% for business. By definition, it qualifies for a greater write off than a passenger vehicle because of it's use and the fact that it is a greater than 6000# and has a cargo area (truck bed). I never claimed this for depreciation previously and have only claimed expenses in the mileage rates. Can I claim this as a section 179 this year or at least claim depreciation that I never claimed?