2003 Suburban intermittent grinding noise in motor

My 2003 Suburban (5.3L) will sometimes make a weird grinding noise when I first accelerate after being stopped. Seems to be coming from the right side of the motor. It only lasts for a second or two, and if I let off the gas it goes away. The engine sounds completely normal when it is not making the noise. It has been happening more often which is obviously not good. Could be the a/c unit?? I almost think it might be the transfer case, but it sounds more like it's coming from the engine compartment. Any ideas??

Does it only make the noise while the a/c is on? I have an 03 suburban and it was doing the same thing. It only made the noise if I accelerated with the a/c on. The a/c belt was having trouble turning the compressor and the belt tensioner tries to make up for the slack in the belt. Which in turn, makes the tensioner flutter so violently that it smacks the transmission cooling lines that are routed directly underneath. That's where the (grinding/rattle) noise was coming from. My suburban is at the dealer as we speak and as soon as I get the answer from them and whether it's covered under the warranty. I'll let you know.

my 97 is making a grinding noise on accereration and I was told that it had to do with the transfer case...switched to 4 wheel drive and it stopped now on the hunt for a transfer case.

It was in fact the a/c compressor. Something let loose inside and metal shavings got into the lines. That's why the compressor didn't want to turn. Brand new compressor, orifice tube, inline filter & belt tensioner. flush & refill system. $1600 including labor. (100% covered by the warranty)
WHEW,That was close!

my 97 is making a grinding noise on accereration and I was told that it had to do with the transfer case...switched to 4 wheel drive and it stopped now on the hunt for a transfer case.

If you have the NV241 T-case. Its quite possible, The snap ring is broke, that holds output shaft to the case. All one would have to do is, pull driveline, then pull 4 bolts from extention housing on tranfercase. Should be broken snap ring right there, that retains case ball bearing. Only problem, if its been driven some time while grinding, it could damage the mode fork. Then, you can get OEM snap ring again, or an aftermarket(much better) snap ring setup. Just a thought for you :)

It was in fact the a/c compressor. Something let loose inside and metal shavings got into the lines. That's why the compressor didn't want to turn. Brand new compressor, orifice tube, inline filter & belt tensioner. flush & refill system. $1600 including labor. (100% covered by the warranty)
WHEW,That was close!

Thanks, The noise goes away when I turn off the A/C, I guess that's it. Did you have extended warranty??