My wife was leaving work today and the 2007 Lexus GX470 won't move. Reverse or Drive. Scanned it but no codes. The AT/P, Tire pressure, VSC and the Center Lock Dif light are on. When you push it from R to P, you get a grinding noise for a few seconds. I did figure out if you put it in 4WD, it drives normally. I did notice the parking brake lever won't lock in place when you try to apply it. She says she hasn't run over anything and it ran fine going to work. She did say it seemed to lose power going up the hill coming back from lunch. I was able to drive it home in 4WD. Any ideas?