Mine made the same sounds. Sounded like something slamed shut under the hood on the passenger side when you rev the motor up past about 2000 rpm. Do yourself the favor and pull the washer spacer out from behind the hub on the compressor clutch disc. I used a c-clamp to hold the clutch disc to the pully, so I could remove the bolt out of the center. The clutch hub slides off of a spline shaft, may have to use a flat blade screw driver to help it start sliding off. I am in Utah right now and pulled a 24 enclosed trailer with 6 four wheelers in it (1500 miles). a/c worked flawlessly all the way here.
Joe