My new ride, '14 F150 STX 4x4, with the "little engine that could" the 3.7V6 . Really impressed with this engine, it has the 3.73 limited slip rear, and has 50hp more than the 2v 4.6 I traded. Plan to go 1500-2000 miles on factory fill, change, even out to 5k, change again, then let the OLM decide from there. I drive 40-50k a year, mostly cruising speeds,and never tow, haul the usual stuff...trash, furniture, an occasional load of firewood, so should serve me well.