GMC 1994 Yukon Owner's Manual page 204

When You Are Ready to Leave After Parking on a Hill
I. Apply your regular brakes and hold the pedal down while you:
Start your engine;
Shift into a gear; and
0
Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you're pulling a trailer. See
the Maintenance Schedule for more on this. Things that are especially
important in trailer operation are automatic transmission fluid (don't
overfill), engine oil, axle lubricant, belt, cooling system, and brake
adjustment. Each of these is covered in this manual, and the Index will help
you find them quickly. If you're trailering, it's a good idea to review these
sections before you start your trip.
Check periodically to see that all hitch nuts and bolts are tight.
Trailer Light Wiring
See "Trailer Wiring Harness" in the Index.
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