GMC 1998 Savana Van Owner's Manual page 196

Total Weight on Your Vehicle's Tires
Be sure your vehicle's tires are inflated to the upper
limit for cold tires. You'll find these numbers on the
Certification label at the rear edge of the driver's door or
see "Tire Loading" in the Index. Then be sure you don't
go over the GVW limit for your vehicle, including the
weight of the trailer tongue.
Hitches
It's important to have the correct hitch equipment.
Crosswinds, large trucks going by and rough roads are a
few reasons why you'll need the right hitch. Here are
some rules to follow:
The bumpers on your vehicle are not intended for
hitches. Do not attach rental hitches or other
bumper-type hitches to them. Use only a
frame-mounted hitch that does not attach to the
bumper. Do not use a ball hitch, because it could pull
the bumper loose.
If you'll be pulling a trailer that, when loaded, will
weigh more than 4,000 lbs. (1 800 kg), be sure to use
a properly mounted, weight-distributing hitch and
sway control of the proper size. This equipment is
very important for proper vehicle loading and good
handling when you're driving.
Will you have to make any holes in the body of your
vehicle when you install a trailer hitch?
If you're using the wiring provided by the
factory-installed hitch, you should not need to make
any holes in the body of your vehicle. However, if
you have an aftermarket hitch installed, you may
need to make holes in the body.
If you do, then be sure to seal the holes later when
you remove the hitch. If you don't seal them, deadly
carbon monoxide (CO) from your exhaust can get
into your vehicle (see "Carbon Monoxide" in the
Index). Dirt and water can, too.
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