According to Hollander interchange the 28-30 Sr, DA, and DB are the same. Also, 27-28 Dodges are the same. This is the carrier assembly only (3rd member). The 30-31, 3/4 ton 120" wheelbase Dodge truck, Dodge Graham 27-28 1/2 ton, are the same. The 1930 DD is different; even the ring and pinion are different.