Grinding noise between 30-45 mph, usually when held at consistent speed. Acura dealership diagnosed the problem (and the mechanic from the dealership said this was a sound he had definitely heard before from other Acura owners) and quoted $2800 for a new torque converter.
A second opinion from an auto shop (although we were not able to recreate the grinding noise), said that if Acura said it was a bad torque converter, then it's not just the torque converter that needs to be replaced, but the entire transmission as there would be bits of metal and debris floating around the transmission,
Took my car to Dealer in CT. and they replaced the Torque Converter at no charge. Noise and grinding are now gone. Feels very tight, like it felt when new. Noticable differance in gas mileage...worse at first..starting to get better 2000 miles later. So far no complaints. My sister has the same car/year and had same problem. She took it to another dealer and they replaced the T/Q at no charge also...and she didn't have the extended warranty.