1999 GMC Sonoma Owner's Manual - Page 204

yellowblue When You Are Ready to Leave After Parking on a Hill 1. Apply your regular brakes and hold the pedal down while you: 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 system. 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. D Start your engine; D Shift into a gear; and D 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. 4-54