My grandma wishes to transfer her property to me using a QuitClaim deed, however she has an existing Will stating the property will be sold and separated among her living children. Does or Will the QuitClaim deed void her Will?

The deed take precedence over the will since she is still alive. The will only becomes effective upon her death. So if she transfers the property to you now then there is nothing left for the estate to deal with as far as that property is concerned. It doesn't void the will, it just removes that property from her estate at the time she passes away.