Weird 4wd problem

[Alex Martin]

Hey guys, i posted a while back about this problem and did everything i was asked to see if i could fix it. Im not in a much better place with way more tools and a lift so hopefully i can finally fix it. I have a 2005 gmc yukon slt with 4wd. It is having a weird problem where it gets stuck in 4 wheel high. The only time it can get out of it is the second i start the car it will change when pressed but about 15-20 min later it will go back into 4 high. It has even tire wear (all about 10/32nds) it does have the "service 4 wheel drive " message and an abs light but no scan tool i have used has given me a conclusive answer. Do any of you have ideas on what it could be or a quick way to keep it in 2wd? Im scared taking the front drive shaft out could just cause problems.