Once you enable the 3D option, the 3D Translate tool becomes available and you will see direction arrows appear around the pivot points to indicate the different axes.
You can click on the direction arrows to move your layer on only one axis. If you click anywhere else, the layer can move freely on two axes at once. Once the arrow is selected, it will turn pink.
|•||3D Rotate Tool|
|•||3D Scale Tool|
|•||3D Transform Tool|