I have a 2007 GMC Yukon XL 1500 SLT. It has 93000 miles on it, when i put the vehicle in 4x4 i get a loud whirring/wining noise from the front end. It also pulls very hard to the right side. I have had dront differential fulid changed but did not fix the issue. I was thinking wheel bearing or alex issue? Any thoughts/help??