Browse Detroit DT12-OA (5TH GEN OVERDRIVE) Transmissions for sale on MyLittleSalesman.com. Compare prices, photos, and seller details across 5 listings. Detroit DT12-OA (5TH GEN OVERDRIVE) Transmission pricing ranges from $9,995 to $9,995 based on recent marketplace data. Filter by condition, price, or year to find the right Detroit DT12-OA (5TH GEN OVERDRIVE) Transmission.