Trying to import a 3ds Max animation

So I made this test spring animation using a path deform. I then copied the spring in it's most extended state and collapsed it to an editable poly. I put a skin morph over that and had it follow the faces of the original path deform strong. I found out that that's not an exportable animation(exporting to FBX).

I Have been trying to find a way to replicate this growing spring effect using MegaFier and morph targets, but it either takes too long to do, and it doesn't animate the way I'd like it to. If anyone knows a way to get this kind of growing effect and then being able to import it into unity, I'd very much appreciate it.