One problem related to transmission not engage has been reported for the 2003 GMC Yukon. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 GMC Yukon based on all problems reported for the 2003 Yukon.
Vehicle suddenly and automatically switched from 2 wd to 4 wd low. Driver did not engage 4wd low system which requires to 1st place transmission into neutral then select 4 wd low button. Driver momentary lost control of vehicle (steering) but was able to safely move vehicle to side of road. Driver and occupants were jointed forward with impact of engagement of low gears and immediate loss of speed.