Let me know where your grandparents were born, perhaps I can help.
The oldest Gleasure line I am aware of is from Michigan.
They descend from Irish Palatines and emigrated to Canada in the late 1840's/early 1850's. The family then moved on to Michigan and farmed in the Brown City area. Descendants from this family are still there.
Regards,
Richard Gleasure
Calgary, Alberta