2004 GMC Canyon Owner's Manual - Page 345

{CAUTION: Getting under a vehicle when it is jacked up is dangerous. If the vehicle slips off the jack you could be badly injured or killed. Never get under a vehicle when it is supported only by a jack. {CAUTION: Front Location If the flat tire is on the front of the vehicle, position the jack to the rear of the front tire in the pocket off of the frame. If the flat tire is on the rear, position the jack under the rear axle and get as close as possible to the shock absorber. Raising your vehicle with the jack improperly positioned can damage the vehicle and even make the vehicle fall. To help avoid personal injury and vehicle damage, be sure to fit the jack lift head into the proper location before raising the vehicle. 5-81