A/C compressor making growling noise

Hello to all...i have a 95 jimmy with a noisy compressor...when i turn the a/c off, the noise goes away...the freon pressure level seems ok...ive added the 2oz can of oil/R-134 quick charge and it seemed to work for a while...when i first start the truck, the compressor is quiet...after running for a while when i restart, the compressor makes a rhythmic growling noise...is my compressor bad or is it just the clutch?...thanks in advance for any suggestions...:grinyes:

More likely the clutch bearings...