1998 GMC Sonoma Owner's Manual - Page 211

When You Are Ready to Leave After Parking on a Hill 1. Apply your regular brakes and hold the pedal down while you: 0 0 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 trailer in 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 toreview these sections beforeyou start your trip. Check periodically to see that all hitch nuts and bolts are tight. Start your engine; Shift into a gear; and 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. 4-55