D4

Caterpillar introduced the first Caterpillar D4 in 1947 starting a serie which lead from D4B, D4C, D4C series II, D4C series III, D4C XL series II, D4D, D4E, D4G XL (Tier2), D4H, D4H XL, to todays latest Caterpillar D4K2 in 2012.