1996 gmc yukon wont shift out of park and when it does it don't stay on 1996 GMC Yukon

i have a 1996 gmc yukon and its been giving me he**. First it started with the rockers was knocking got that repaired, changed spark plus and wire oil fliter and radiator fluid all repaired, ha that was the beginning,the break booster went out got that repaired, the fuel pump went out change the relay and fuel filter rapaired all of that, then the fuel injector went out got that and now i cant get it out of park please help me with this lemon trying to get it to a dealership so they can continue to fix on it i want to trade it in hopefully not for another lemon!!!!!!!!!!!

Asked by for the 1996 GMC Yukon
Now you know why GM went broke, they had some big time quality issues. The new ones seem much,much better, which makes me very happy. I used to be a GM journeyman tech.