I know there are quite a few on here who tow a Honda CRV. Our 2006 developed a noise (growl?) when making a hard left or hard right turn. I took it to the dealer today and they said the problem is pretty common. Appearently the differential fluid "wears out" before it should. It is supposed to last 40,000 or more miles and ours only has 20,000 on it. I am not sure exactly why but they replaced it under warranty.
I always thought oil and fluids were not warranty items.
It has nothing to do with towing it but thought I would post here as a FYI in case your CRV developes the same symptoms.