my 96 jeep cherokee makes horrible grinding noise while driving?

[thadeisel4t0]

i have a 96 cherokee all time 4wd and it just started makin this horrible grinding noise as im driving no noise while in idle and noise starts to quiet down when i let off the gas but no loss of power and trans dosent seem to be slipping could this be a transfer case or front diff any help please...