Well it looks like we've all figured out this thing sucks.. I tore mine down to the bones but stopped once I was going to have to start disconnecting the tubes on the lower part of the cleaning trays under the ink cartridge holders and it got me no where closer to the inner part of the feeders other then an extra 1/2 to 1 inch of room but not in a very good way when your having to hold half of it, moral of the story don't screw with trying to pull it apart to get a better angle at the gear. I tried loctite and it literally lasted for about 15 prints so not much help there. What they should've done was had a square shaft on there or a double key pressed into the bar that way it had more grip instead of grinding out a hole in the gear. they wouldn't be throw away items if they put a little sense in lasting designs instead of "Hey it printed a page so it works, right?" HP's new model should be "Built to work, but not to last".
The only Solutions I can think of are
--drill a small hole directly threw the gear and rod and put a pin threw the hole and loctite it in place.
--move the gear to the side and clean off the rod where pieces of the gear still are and find a VERY good glue that bonds to plastic and metal and put it on and then slip the gear back on and glue the outside of the gear to the rod too (still looking for the glue but needs to be liquid).
--someone mentioned earlier about using a 2 part material to put on the sides to grind it and bond it but what might work instead is to move the gear over to the side and put that on the rod and pack it on the and rotate the rod so that is grabs the gear marks and essentially becomes a replacement gear, of your good enough it might just work .
--Else take the thing out back and blow it up...