Greetings from GoVacuum,
If you have replaced the clutch already, then this can really only be one other problem, and that is the roller brush. If the roller brush's bearing have locked up, and the brush is no longer spinning, this is going to cause the clutch to make that horrible grinding noise, and a lot of people incorrectly think automatically that the clutch needs to be replaced.
Here's a very easy way that you can test the roller brush on your Dyson to see if it may have gone bad. In 10 years of fixing and selling vacuum cleaners, I have never seen such a cheap roller brush that's in the Dyson DC07 models with clutches, unfortunately this is notorious problem we see on this particular model.
Ok, so to test out the brush, make sure the vacuum is unplugged, and turn it upside down. Remove the 3 plastic screws on the bottom plate, and remove the bottom plate to expose the brush completely.
You may then simply pull upwards on the roller brush, and take the brush out of the belt that is wrapped around it. After the brush has been completely removed from the vacuum cleaner, hold the brush with only your pointer fingers in each hand, and only put your pointer fingers on the outside of the bearing caps on each side of the roller brush.
While holding only the bearing caps with your fingers, try to spin the brush with your thumbs. The brush should spin freely in your fingers, and you should get a good 5 or 6 rotations with each spin.
If the brush doesn't spin, then your roller brush has gone bad. Espcecially with home that have long haired pets, or females, the hair gets between the bearing cap and the bearing inside and causes the plastic caps that are covering the bearings to heat up, ultimately causing the bearing caps to melt, and finally the bearings sieze, and the brush will no longer spin freely which is why the clutch makes that awful noise.
Good news is that the roller brush is not as expensive or as difficult to replace as the clutch was. You may purchase the DC07 roller brush here;
Genuine Dyson DC-07 Roller Brush for Models That Use a Clutch Part # 904174-01
If your roller brush does spin, then I'm baffled as to what could be causing the clutch to make noise, but I'd like to try and help you figure this out.
Please send me an email to firstname.lastname@example.org
, or just request a clarification request here on Fixya, and I'd be more then happy to try and diagnosis this Dyson further for you.
If this Solution was helpful to you, please rate the repair as helpful by clicking on the 4 Thumbs Up Icons in the top right hand corner of this solution.
Thank you so much, I hope that this helps you.