He had a 4035 that had a noisy door, what we normally do is replace the gears. Well another tech already did this, still noisy.
This is what he found, where the duplex metal bracket butts up against the pre-registration assembly. The Plastic gets a groove wore into it. He simply filled in the groove with soldering iron and piece of plastic and smoothed it out with a file.
I wanted to see if it would be a fix without ordering gears. So at the shop, we had two machines making the same noises. He grabbed the Pre-Reg and did the same thing with the soldering iron. Put it back in. Both of them sound like new ones with out ordering any gears.
Let me guess, that noise starts up around the 900K mark on copy count. I use some liquid electrical tape to fill in the groove. The noise if from the gears bottoming out when engaged. Took me quite awhile the first time I encountered this problem to figure out what the real cause was.
