I have a auto 2010 xb with 14000 miles. I have recently noticed a loud metal to metal noise coming from the front of the car when i put it in gear. It only does it when it is cold It's a high pitch knock sound. Do you think it is the brakes, transmission or axle???

 

most likely just your transmission switching gears. noise will happen with the lack of oil around the gears in the cold. I wouldn't worry about it.

 

Have someone put it in gear for you while watching the engine, hood up. see if you can locate the noise that way. The engine will move a bit on the mounts, but if one of the mounts has failed it will move a lot and could be the source of the noise.
As mentioned above, it could just be normal.

 

The past few mornings i put the car in gear with the handbrakes up on flat ground and i hear no noise.