Well it was bound to happen. After four years of hard use, the HF44142 3-in-1 started to make some noise in the headstock. I was expecting something along that line since I have used (read abused) this machine pretty hard. So I pulled the gearbox plate

First, drain the oil -- remove the oil drain plug (see arrow). Next remove the cap screws that cover the gearbox. Note: Since this is an angle plate, there 8 cap screws on the headstock side and 2 on the cabinet side (see below)

Be careful, don't rip the rubber gasket -- it can be reused (with a bit of silicon gasket cement to help hold it in place). The next pic shows the inside of the gearbox. Notice that the two main drive gears are made out of plastic, but the transmission gears are made out of metal. I guess this is a safety feature so that the plastic gears break before too much torque builds up in the leads crew and the gears shear before the lead screw bends, or the operator gets hurt.