Ancestors property

1. The property is in the name of your grandfather- How he got that property is unknown? Then property link is missing.

2. WITH OUT Will - Property distribution after death in question?

 a. The property of a Hindu male (dying intestate) is sharing among his heirs according with section 8 and 9 of The Hindu Succession Act, 1956

 b. The surviving sons and daughters of the intestate get equal portions.

Hence your mother and aunt can claim their share in the property and file a partition suit. 

Thanks for your time and reply.

The property 'was' in the name of my grand father, without our consent and without us knowing, they have partitioned it among them both.(last november)

Property was sold to my grandpa from some other person, property links are proper.

By Failing a suit, will this be property be protected from being sold to someone else or to be used for agriculture

Thanks again

then as told by learned adv you can file a partition suit to claim your share and also obtain an injunction over your uncle to restrain him from proceeding with any sale of the disputed property