Starting a thread for gearboxes.
Catt, There have been many discussions regarding cast iron versus aluminum gearbox cases. What have you seen over the years regarding the two? I can see how cast iron would be very strong, but to be honest I've seen gearboxes torn up inside but the case castings were fine.
Me to. 4-5 aluminum with broken cases but never saw a cast iron case broken.
That I know of there are no white papers, studies or other specific info I could ever find related to snowblower gearboxes. My base has been formed by reading lots of net postings from posters who seem knowledgeable and working on quite a few.
Point 1. Strength.
The impression I get is cast versus aluminum is mainly for strength when taking a hit. Cast is one added feature in making a machine more robust boosting it into the category of heavy duty, industrial or commercial.
Point 2. Long term wear.
It’s possible that the added rigidity may have a miniscule effect on wear over 20-30 years but from my estimate if both a cast and aluminum with the same internals were used in the same service over 30 years the wear would be the same or the difference insignificant.
Point 3. Robust build.
Cast gearboxes often used to come with two roller bearings or heavy flanges. Ariens use to used two roller bearings up to about 2004. I think they are now all bearings in Ariens cast and aluminum. There are generally more support parts in a cast. The trust washers and collars may be more robust than used in an aluminum. An MTD is low end and collars often break in those with an unusual but solid hit. So casts, depending on the make, my have more and better internal parts even if the gears are similarly sized to an aluminum. Generally though, aluminum gearboxes are simpler with less robust parts. There are worm differences also with smaller diameter one piece shafts with a milled worm versus a separate replaceable larger diameter worm on a larger shaft.
Point 4, Utility.
A cast would be good for commercial and industrial use. A small company would have one for their lot where the operator may not be so caring about use so a beefier box good. Operators may nor be familiar with the lot they are clearing so chances of picking up debris higher or hitting hidden obstructions greater.
A homeowner would be more caring of a machine and knows his area but there are lots of “I got’cha’s” around a house, newspapers, doormats, and kids toys but for the savvy homeowner there is no reason to get a cast over an aluminum. A low end aluminum (Murray or worse MTD) in average home service will outlast the other parts of the machine. For home use with an average driveway any gearbox is fine. For bigger areas with big drives MTD is not so good but passable. A better bet would be aluminum by Murray(low end ok), Toro, or Ariens ((XS), the compacts Ariens is now the size of MTD. The old Ariens gear with a collar was ok).
Point 5, Other.
Yamaha and Honda use aluminum and I don’t know of any complaints about these. They both use 4 roller bearings in the gearbox. Yamaha may have gone to two. There are two Honda dealers in the area I’m fairly friendly with and they have zero problems with the gearbox.
For the average machine in homeowner service I don’t see any need for cast over aluminum unless there is a specific need. Any of the gearboxes on the machines at Lowes or HD seem fine to me for use around eastern Massachusetts. For areas with more snow ok to a point but better aluminums would be good. If someone had a long drive with trees on both sides and old branches fell all the time that get buried then big aluminum or even cast. No benifit to cast without a need.
