How do I properly transfer displacement maps from zBrush to Maya?

As far as understand it Displacement maps use grey scale values for black to white and all greys values in between. So black is usually no displacement and pure white is the most displacement. Grey values in between give you different amounts of displacement. If you look at the map you exported from zbrush all the parts you don't want displaced should be black and the areas you want should be values of grey or white. Sorry I don't use Maya I'm a Max user so it should be, in theory the same! You could try adding a colour correction node to your displacement map in Maya and alter the contrast and saturation. Hope that helps!

In your displacement shader in hypershade, try to play with the middle value and the displacement value.
Can you send me the map and file in a we transfer ?

nicee