I have a 3018 and a L84-7 snowcaster. The snowcaster mounts up on the 3018 just fine. The lift works as it should. I need a belt and it seems like everything should just work. But if you check the attachment charts, the L84 isn't listed as a compatible attachment for the 3018.
So, the question is can I use an L84 caster on a 3018? Or can an L84 be adapted to work on the 3018?
As you have discovered, it will mount right up to the tractor without any trouble. However, it's not listed in the attachment charts due to the engine orientation difference between the 3-digit vs. 4-digit model tractors. The 3-digit models have the engine mounted with the flywheel facing forward, while the 4-digit models have it with the flywheel facing rearward. That results in the PTO pulley rotating in the opposite direction. So if you were to simply hook up a belt following the stock L84 routing it would result in the auger turning backwards.
The good news is it can be adapted to work. I think the easiest way would be to swap out the hitch / mule drive assembly with one off an SB series caster. Or do some cutting & welding on the existing assembly to swap the two idler pulleys (along with the spring loaded tensioning arm) side-to-side. I believe you will also have to re-position the drive pulley farther toward the left on the jackshaft (and that might involve replacing the jackshaft if it's not long enough).
Ditto Ray's notes. It is a bit pricey to buy the new parts and apply them, but if you are a good fabricator then you can mirror image the pulley and tensioner, get the longer driveshaft and get it all to work right. You'll still have the early style auger position - chain tensioner though.
Some here will say you can just run the belt 'backward' to get the right rotation, but my long experience is that you'll have belt problems if you do that.
I have a complete, used SB48 (correct for 3000/4000) that is available here (Pymouth MI) now, if you are interested. Buy the right one and sell the L84.
I could sell as is (ready for maintenance), or service it with all the right new parts for the appropriate price. Get with me off line if interested.
So I rented a trailer, drove to the property and re-installed the points box (with new points and condenser) and the 646 fired right up! I know I need to still remount the coil (don't have a bracket...