Ford 2001 Econoline Owner's Manual page 116

Driving
GCWR (Gross Combined Weight Rating)/Trailer Weights
Rear
Engine axle
ratio
E-450 Stripped Chassis (dual rear wheel)
5.4L 4.10
6.8L 4.63
* Maximum trailer weight for all cutaway (E-350 and E-450) vehicles
must be calculated by subtracting the weight of the vehicle (including
incomplete vehicle weight, and payload which includes second unit
body weight, cargo, and passengers) from the GCW. Otherwise,
maximum trailer weight is 4 536 kg (10 000 lbs).
For high altitude operation reduce GCWR by 2% per 300 meters (1 000
ft) elevation.
To determine the maximum trailer weight designed for your particular
vehicle as equipped, follow the section Calculating the load your
vehicle can tow/carry earlier in this chapter.
Your vehicle's load capacity is designated by weight, not by volume, so
you cannot necessarily use all available space when loading a vehicle.
Distribute the load so that only 10 to 15% of the total is on the tongue.
Tie down the load so that it does not shift and change the weight on the
hitch.
Towing a trailer places an additional load on your vehicle's engine,
transmission, axle, brakes, tires and suspension. Inspect these
components carefully after any towing operation.
Do not exceed the GVWR or the GAWR specified on the
certification label.
Towing trailers beyond the maximum recommended gross trailer
weight could result in engine damage, transmission/axle damage,
structural damage, loss of control, and personal injury.
116
Maximum
GCWR - kg range - kg (lbs.)
(lbs.)
5 897
(13 000)
9 072
(20 000)
Trailer weight
(0-Maximum)
1 361 (3 000)
*
Maximum
Frontal Area Of
2 2
Trailer - m (ft
5.52 (60)
5.52 (60)
)