For those of you dealing with this problem who are technically adept.....
Zuts has told you what causes this problem ...he's absolutely correct, it's the left (gearing ) side bushing - it's wore out..
My CO. had about 5000 of the 3005's....I am one of their techs....
We found that a washer used as a shim on the left ( gear ) side mounting screw would really help this noise..You don't really fix the problem; just work around it..
The mounting screw is one of the two on the left side that mount the Fuser into the printer..There's one at the top and one at the bottom. Place the washer ( about a .020 thick one) between the printer frame and the Fuser flange (that's the place with a hole for the mounting screw.. What that will do is hold the fuser out a little from the gearing, and it won't make so much noise. I forget to say the bottom screw - left side.
Put a little lite white grease on the gears, too ..that will help....
BTW , .020 thickness is about the thickness of 5 sheets of bond paper...it don't take much....
Another thing we found was ( if you are a bit more technical ) the 2 springs that put pressure on the FILM & pressure rollers....if you are able,,,,,cutting 1 & 1/2 wraps off these springs is another work-around.....
Don't try this unless you're sure of yourself..because you only get one shot to get it right...