Grind at start

Just finished testdriving my sister's 97 grand am, and I noticed there's a harsh grind if you start about 1/3 throttle or more. If you roll on the throttle it'll be quiet, but anything harder than a little pressure and it'll grind all the way through 1st, and it seemed like the start of 2nd.

Anyone have any ideas? Transmission and oil filters and fluids were changed not too long ago. Rotated tires last month. Everything else about it works just fine though.

check the hub bearings. On an easy roll, all is good. Under hard acceleration, the bearing will contort, and get noisy.