I read that too. It's posted on the 3rd page of forum 1 page down titled:
USA DC17 Animal with rattling brushbar
Started by Millcreek.
Seems like if you have the old one it's 8mm, if you get a new brushbar you need the 10mm. I just ordered one from amazon and cheapest I could find. But I read somewhere else that the 8mm is not the right size and that's why they make noise and you need to replace with a 10mm. So I ordered the 10mm and going to put it on will let you know.
Also, after reading about this particular model it was made in the US. I have a dc14 Animal and it is by far better than dc17. The suction is soooo much better and have never had a problem with it. I have had it for about 5 years and I clean houses so it gets used everyday......ALOT! It's not as loud and the wand can litterly suck up a t shirt in a heart beat.
I found out that is another filter on the side on dc17 that never knew about. Some say you never have to clean it but I took it out and well it needs a new one. You really can't wash it.
Sure hopes this helps