2007 GMC Yukon Owner's Manual - Page 154

Shifting Out of Park (P) Automatic Transmission Your vehicle has an automatic transmission shift lock control system which locks the shift lever in PARK (P) when the ignition is in the LOCK position. You have to fully apply your regular brakes before you can shift from PARK (P) when the ignition is in RUN. See Automatic Transmission Operation on page 142. If you cannot shift out of PARK (P), ease pressure on the shift lever and push the shift lever all the way up into PARK (P) as you maintain brake application. Then, move the shift lever into the gear desired. Parking Over Things That Burn {CAUTION: Things that can burn could touch hot exhaust parts under your vehicle and ignite. Do not park over papers, leaves, dry grass, or other things that can burn. 154