Unity3d import Maya animation

I have tried every option of exporting an animation(fk/ik) from maya to unity in .mb and .ma format…and fbx too.
Unity always gives error of fbx export when importing …mb file…animation gets imported in an unpredictable way.

My maya animation file size is around 9 mb,im concerned whether unity has some size limitation as when the animation
is further controlled by programming team it behaves weird.meaning we have a horse running animation in loops and we are moving and rotating it in forward axis in unity and its just not working the way it should be…

I want to know ,is it important to export our animation in fbx,when not only FBX(maya’s native one) increasing its file size and not even baking the animation properly??

Which error do you get? and what do you mean by “imported in an unpredictable way”?

Imported in an unpredictable way meaning,mesh gets distorted after baking the animation.but its a hit n trial method,some times it works some times doesnt.
Eror/warning i get is “ImportFBX Warnings:
Skipping influences for ‘cluster1Handle’ because it is marked as ADDITIVE. This most likely means that you are using a blend shape or custom deformer, which is not supported”…
I have one cluster in the animation and no BLendshapes.Deleting cluster doesnt help.