GMC C-Series 2001 Owner's Manual page 178

Before you do anything, turn on the hazard warning
flashers (if they have not been damaged).
When you call, tell the towing service:
D
That your vehicle has rear
D
The make, model and year of your vehicle.
D
Whether you can still move the shift lever.
D
If there was an accident, what was damaged.
When the towing service arrives, let the tow operator
know that this manual contains towing instructions.
The operator may want to see them.
Here are specific towing instructions:
-
wheel drive.
Towing Your Vehicle From the Front
(Front Wheels Off the Ground)
Before Towing
Block the rear wheels of the disabled vehicle. On
vehicles with air brakes, release the emergency brake
system by compressing the brake chamber springs
as outlined in this section. (This is to prevent the
possibility of the emergency brake being applied
during towing.)
On vehicles with hydraulic brakes without an
electric/hydraulic parking brake, release the
parking brake fully by moving the lever to the
-
fully released position.
On vehicles equipped with an electric/hydraulic parking
brake option, remove the propshaft.
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