@DFG56 posted:So, packing the gear box with Red and Tacky didn't change anything unfortunately. So, I used the old auto mechanic trick of using a screwdriver to touch parts of the engine and put my ear to the handle to see what made the most noise. The motor was very quiet.
Is there not a bushing on each end of the shaft that the worm is mounted on ? On all the Samhongsa gearboxes which I have worked on the shaft the worm is on has bearings on each side of the worm and they are captive within the clamshells of the gearbox thus the gear mesh is not user adjustable. That screw with spring should adjust the angle the gearbox shafts meets the motor shaft. I cannot be certain but the shaft coming from the flywheel looks to be meeting the worm shaft at quite an acute angle. That would put a side thrust pulling up on the rear bearing of the gearbox. That in turn would be holding the worm against the worm wheel even though the front bearing is not in place. The rear bearing is acting as a fulcrum. Looking at the grease oozing out of the front of the gearbox makes me think the front bearing is not in place on the worm shaft. I posted photos back around 2018 - 19 showing a version of that gearbox where the worm wheel also acts as an idle gear if you want to look at my earlier posts. The worm shaft however has the bearings I speak of showing in those photos. I have to leave now but will return Sunday night and will re-post those pix when I return. The pix in that discussion are of a Williams / Samhongsa loco with a 42:1 gearbox and I have a series of pix showing what I did to eleminate the whine from the mabuchi 550 three pole motor they are quite prone to whine. Five pole motors push less air around and don't whine as much. All said, I suspect you may be missing the front bearing on that gearbox. j
