One problem related to transmission noise has been reported for the 2006 Honda Odyssey. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Honda Odyssey based on all problems reported for the 2006 Odyssey.
I'm the original owner of a Honda Odyssey 2006 ex-l, I have religiously maintained it and have used Honda filters, oils and lubricants, have done oil changes every 7,500 per Honda maintenance schedule and replaced tranny fluid every 15,000 miles, especially after knowing this has been an issue with previous Odyssey's and current ones. At 52,000 miles I had to replace a broken motor mount (known issue that Honda won't acknowledge) thankfully extended warranty covered it. At 90,700 (my extended warranty expired at 85,200 miles) my transmission started making a whining noise (I have had 2 independent mechanics and a Honda dealership verify the tranny is going south). In addition to the motor mount and transmission issues, this vehicle has had recalls to replace front brake pads, brake master "o" ring, power steering pump and paint peeling. For a $33k vehicle, it sure is a lemon.