I m hearing a knocking noise in my discovery, very loud, I had to park, anyone knows what it is? someone told me it might be the vacum pump

 

We will need more info ,,,,,,,year? ,,,,motor?,,,,miles? or Kilometers?
Over heated? ,,,,,Low oil?
What was going on when it started?
MIL light On?

Going from what you said so far your motor is toast.
No vac pump on most Disco's thats why we need more info.