3DSMax animations issue with Unity

I am experiencing this issue when the animation guy sends me some animation that fits perfectly in his preview in the 3DSMax but then when I try to run it on Unity the objects involved acts strangely.

Example: we are trying to get a human character to handle a single key for another human character. There a three models and all of them have the same animation frames. All of them have the same scale and rotation and initial positions according to the 3DSMax example. But when I test run it, the key goes somewhere else it wasn´t supposed to go! I also happened when we tried to get the character to handle a rope. The rope started to not match the character hands in Unity.

Does anyone have this issues too? Maybe this is something simple we are missing!

Thanks