Ford 2004 F150 Owner's Manual page 180

Driving
Your vehicle's load capacity is designated by weight, not by volume, so
you cannot necessarily use all available space when loading a vehicle.
Towing a trailer places an additional load on your vehicle's engine,
transmission, axle, brakes, tires and suspension. Inspect these
components carefully periodically during, and after any towing operation.
Exceeding the maximum GCWR could result in extensive damage
to your vehicle and personal injury.
Do not exceed the GVWR or the GAWR specified on the
certification label.
Towing trailers beyond the maximum recommended gross trailer
weight exceeds the limit of the vehicle and could result in
engine damage, transmission damage, structural damage, loss of vehicle
control, vehicle rollover and personal injury.
Regular Cab 4x2 (126" wheelbase)
Engine Rear axle ratio
4.6L
4.6L
5.4L
5.4L (w/17"
tires)
5.4L (w/17"
tires)
180
2004 F150 (f12)
Owners Guide (post-2002-fmt)
USA English (fus)
Maximum
GCWR-lbs.
(kg)
3.55 11500 (5216)
3.73 12000 (5443)
3.31 12000 (5443)
3.55 13000 (5897)
3.73 13500 (6123)
I n f o r ma t i o n P r o v i d e d b y :
Maximum
trailer
weight-lbs.
(kg)
6500 (2948)
7000 (3175)
6800 (3084)
7800 (3538)
8300 (3765)