Noisy Laserjet 4350

I am in the same boat, we have 5 of these and one 4300, all really loud. Let me know if you come up with anything. I have been trying for a while but cant find anything.

Check the fuzer gear drives and the accompaning
gears that drive it. Use your thumb and try to turn the rollers, one way or the other.

Try this HP link http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=bpl12433&prodTypeId=18972&prodSeriesId=412160&locale=en_US#N10147

Let us know if this doesn't work.

I have received a white paper from HP concerning this issue Document number C00429483. They say the it's because the drive gear engagement from the swing plate assembly and the fuser is off. You may have black residue around the gears of the fuser.
they say it's because the power supply has slipped down during shipping. There's a work around, and if this doesn't work you have to replace the swing plate assembly part # RM1-0043-060CN.
The work around is to remove the formatter and the left cover exposing the 3 screws on each side that hold the fuser cross member. rotate the cross member toward you and the rear down (inside). While holding in this position you tighten the 6 screws. It worked for me on 2 out of three printers.

Kpalmer,

Sound like you need the swing palte assmly.
This kit will resolve your issue.
here is my email for the fix
lghany@tsaworld.com

We have had this problem with the 4350 a lot, but it is coming out of the duplexer area. There is an assembly in there that wears after a short time (Swing plate assembly). HP will fix this under warranty, if you still have warranty.