One problem related to transmission fluid leaking has been reported for the 2005 GMC Yukon. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2005 GMC Yukon based on all problems reported for the 2005 Yukon.
Winter 2014, connecticut - backing out of driveway peddle felt mushy and going down farther than normal. Drove son to school quarter mile to school and noted the lack of braking ability. Luckily rolling stops and keeping distance from other cars allowed me to get back home. Looked under car, dripping brake fluid from under middle of card. Had the sense to have it towed to the dealer; for the $2400 estimate, they also said that my transmission lines were leaking so estimate also included the labor/parts to replace both sets of lines to fix both line related issues. I've also had the miss pleasure of having to replace the transmission ($3500) this year as well. Slipping and eventually it was going to cause an accident so had to open the wallet for that. Another issue (electrical) - I shut the car off with the blower motor on (heater in the winter) and the blower motor stayed on even after the car was shut off, no keys. It continued to run and would have drained the battery had I not disconnected the battery. Pulling the fuse had no effect. ($600) I have also had to replace both the front airbag sensors in the front bumper. One went and two weeks later the other went. No impacts, they just died. ($1200 for both). I have also had to replace the rear air shocks ($2500) I bought this car used (supposedly gm certified)) from a chevy dealer not more than 3 years ago with 75k miles. I now have 99k miles. As I sit and type this all down for this submission, I realize just how much has gone wrong with this car & matches up with other owner statements on this website.