legal document

The trsnsfer of property from your grandmother to your father's name is absolute already or the mentioned  transaction is deemed as transfer of property  ???

CLearify;

However if your Aunt has signed the settlement , that was suppoused to be registered ;; if she would not dispute the document and is honest enough to accpet to have released her share let her execute a release deed;

Though the signed document could be used as an evidance if she raises claim, but a registered document conifers much better tilte. 

My be ,but they can as you have no registerd document.Get arelease deed from your Aunt as she is alive now. Keep your title clean.

I don't know how was the property transferred from your grand mother to your father's name ?

As ia sked earlier also.

Need to know the mode of transfer ?

I don't know how was the property transferred from your grand mother to your father's name ?

As ia sked earlier also.

Need to know the mode of transfer ?

That means total of thre heirs;; two sons one daughter.

If Your your aunt has released her share that need to be registered document and the release shall be in your father's name. If you won't get a registered document tommorow the heirs of your Aunt coul claim the share. SInce u have a dcumnet but that is not registered can be quastioned and disputed. It is better to cure the infirmity...

What is the nature of property (Agricultural land, plot or building)?  In whose name it is standing from 2002?  Who is enjoying the benefits?  To whom it is being transferred now?

If it is within a family transfer now, a simple registration now as gift deed is enough.  Even if it is a sale if the property is being enjoyed by your father as per Revenue/Municipal records, there is no necessity of your aunt's signature as family settlement need not be registered in some states.

If your aunt is living, a witness signature in sale deed is more than enough.

The facts as posted lacks clarity; your piecemeal posting adds to the confusion. Please post simple facts -

How your grandfather had acquired the peoperty?

How and when it was transferred to the grandmother? 

How and when it was further transferred to your father?

Is the grandmother alive as on date?