Thanks again for the excellent post / guidance provided by Superglidesport in his instructions provided for replacing the plastic JD impeller / fan with a metal impeller / fan (i.e. AM109105 for metal impeller / fan). I used this to finish mine yesterday and everything appears to work fine. If doing this where ventilation is available, it is also a good opportunity to apply some primer / paint to the inside of the snowblower housing. Mine was pretty rusty since it had been used commercially for 3 winter seasons in Wisconsin. These instructions would also be valuable if one needed to replace the gear drive unit as well (ouch..., currently above $600 with no replacement parts). If nothing else, I'd like to see a replacement cover available and a plug that doesn't use a hex head drive (e.g. an external square drive head plug replacement).
It is the following GTT post:
47 / 54 Snowblower Impeller Installation (It should be a 'sticky.')
If in doubt, go back and review the instructions while going through the process (I missed / forgot one step that caused me grief)....
I have some minor observations / suggestions based on my replacement that might make the process a little bit easier; as always YMMV....
I found the re-installation of the auger / drive shaft / impeller to be the most challenging phase of the process though getting the chain drive gear and
shaft collar off were also harder on an older, well used machine. Suggest the application of anti-seize (e.g. Moly / MoS2 or Copper / Cu) to parts when reassembling in the event you have other issues in the future and need to remove the auger. I also cleaned surface rust from the 1" drive shaft with fine grit (320) emery paper as well as a light anti-seize coating for the gear and shaft collar.
I was pleased that with the application of a penetrating fluid / time I was able to get the small hex key set screw out of the shaft collar and the larger ones for the impeller mount. I've applied anti-seize when reinstalling these. The shaft collar had a second hole that may have been for balancing, but it only had one set screw.
I'm always afraid of stripping the hex head set screw / plug heads if they're stuck. The hex drive plug on my SB gear drive was rusted in place and ended up removing the cover to inspect the gear oil level while the auger was out of the housing. This is basically the only time the housing will be cover side up.
The drive photo is of the gear drive without the cover is attached. I applied additional 'form-a-gasket' material to help assure a good seal.
One suggestion is that you go ahead and remove the gearbox support bracket once you've removed the two bolts from the gear box prior to removing the auger assembly. It isn't difficult to remove or reinstall (2 bolts with 15 mm heads / nuts). I found that when replacing the auger assembly it made it difficult to get the auger, impeller, and shaft into its housing. Much easier when the bracket is out of the way and was no problem to re-install.
Another is to delay installing the shear bolt (1/4" Grade 5 bolt / nylon locknut) on the impeller until after the shaft has been inserted into the rear bearing.
Having the impeller free on the shaft makes it easier to install the auger assembly. The shear bolt and its nut are accessible as you might need to replace it in the event it needs to do its job of breaking to protect the impeller.
I used 2x and 1x lumber blocks, boards, etc. to lift up and support the auger assembly while working to install the drive shaft into the rear drive bearing.
To get the drive shaft into the rear bearing, once the auger assembly is supported and the drive shaft is butted against the rear wall of the impeller housing, it was helpful to reach into the chute opening (with the chute pointing to the right) behind the impeller to guide the shaft into the bearing while using the other (left) hand to push the auger assembly in once the drive shaft is aligned with the bearing. I was lucky that the chute happened to be oriented to the right.
To align the two auger end bearings with the bolt holes, I found that the fairly narrow Harbor Freight oil filter wrench had jaws wide enough to grip the bearing plate / support and help orient everything. Any other wide jaw narrow thickness adjustable wench should work.