Joe Muehl

i also have same problem (grinding noise at highway speeds)..dealer said it was the torque converter but they were too busy to fix it because they were so far behind due to the gm strike a couple months ago. I took it to a local transmission shop that was recommended by a family member and they said the trans was completely "burnt up" so they rebuilt it. I left the shop and everything seemed good for about 2 days then started making the noise again. Its back at the shop and now they are telling me that its the valve body in the trans...luckily its under warranty so it'll be n/c for me. I hope this fixes the issue