Haleivi, the source for the year (which is actually 5408, not 5480 as I posted earlier) is in Zohar Parshas Toldos, Page 30, Os 68 in my edition (Sulam). This is the year of Techiyas Hameisim.
The source for the fact that the time of Moshiach has never been revealed at all, and that it is foolish to try to calculate it is from Medrash Haneelam, Parshas Breishis Page 131, Os 347 in my edition (Sulam).