If you press G you can move the selected object in all directions. You can constrain the move to an axis by pressing X, Y or Z after the G. But I don't like that method too much. I prefer the actual gizmo, the move tool with the arrows, or the circles for rotation, or the one for scaling, with all three axes showing clearly, and in great part I like that better because it shows me where the object's axes are, but mostly because I can easily click and drag the red arrow and I know my movement of the object is going to be constrained to the X axis.
Well, I don't know if I changed something by accident in the preferences or what did I do, but for a few days now, if I click and drag on any of the arrows, it doesn't constrain the movement to the X axis, it just lets me drag it anywhere in any axis as if I had pressed G.
I keep going up and down the preferences and I still can't find what I did. Help me figure it out please?
And by the way, is there a way to assign a letter to enable each of the gizmos, like many 3D programs have Q to bring up the move tool, W for the rotate tool, and E for the scale one. I went through the whole list of key shortcuts and I can't find it.