What is the difference between a 4x4 and a FX4?
The available Ford Work Solutions package is offered on XL and XLT models and adds an in-dash computer that is customizable to suit commercial users and fleets. Also available is the FX4 Off-Road package (4x4 models only) that includes an electronic locking rear differential, all-terrain tires, hill descent control, skid plates and Rancho shock absorbers.
http://www.edmunds.com/ford/f-250-super-duty/2012/ -- here's where I found that info. Hope it helps
FX4 describes the trim level of the truck, which is a 4dr SuperCrew 4WD Flareside. 4x4 simply designates a vehicle with 4 wheel drive.
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