VF Storm wagon transmission problem

I bought a VF Storm wagon V6 in June. After driving it for a few days it developed a knock and also a thud. The thud occurs when you take off in Drive, but if you let the car creep forward then press accelerator it wont do it, or if you press the accelerator very lightly at take off. The knock clunky sound occurs when you select reverse, but not at the time reverse is engaged, it happens after you press the accelerator. I took it back to Holden when it had about 2800km and they told me that they loosened the k-frame and re-tightened it. The noise was still there when I drove it home. Next time Holden had the car for three days, but told me it was normal when I picked it up. I wasn't happy and went and got independent reports stating that there is something wrong, but they couldn't pinpoint where, but they did tell me that they think it's in the transmission. Holden then organised for an engineer to check it, and he found then problem to be the transmission. A new transmission was fitted, but the noises were back a week later. Have you heard of this problem? Also are we entitled to a refund?