I have a 8 cylinder 7.4L suburban. A friend had vehicle in drive but not moving and engaged 4wd. What kinds of problems could result from doing this? The shop said I needed rear axle housing 3/4 ton w/9.5" ring gear, transmission, and a transfer case to be replaced with used parts. I am wondering what could have occurred by just pressing the 4wd button while the vehicle was not moving but in drive. Please let me know if this sounds right.