I, too, have a 2006 HiHy and the owners manual is most clear on the towing capacity. It is indeed 3500 lbs. I have towed more on accident - over 5000lbs - and it was so capable I didn't even realize it.

With that being said I would not purposely tow over 3500lbs for an extended trip. I would be concerned it could void the warranty.

 

This post is to clarify the issue of towing capacity of 2006 HiHy. I went to dealer the other day and I was told the towing capacity is 2000lbs. Pressed hard on this issue and asked them to give me a definitive answer and be responsible for the answer. Eventually, a mechanic checked if there is a transmission cooler. The cooler is very easy to find. It is behind front bumper and in front of the driver side wheel. The towing capacity is 3500lbs.