BX 5450 Snow Thrower Reduction Gearbox Problem

   / BX 5450 Snow Thrower Reduction Gearbox Problem #1  


Bronze Member
Feb 4, 2014
Red Sox Nation
'06 Kubota BX2350
Is there a way to get the chain back on the reduction gear and drive gear without having to disassemble the entire thing? The gear's set screws, despite using Locktite, wiggle out and the gear comes loose then off comes the chain. It's very frustrating because it doesn't appear to be an easy repair. And yes, apparently I need to check the set screws more often. I'm practically ready to weld the set screws in place because I've had it with this problem.

Note: the gear is not shown in the below picture

   / BX 5450 Snow Thrower Reduction Gearbox Problem #2  
After you get it reassembled drill a small indentation in the set screw hole then lock tight the set screw.
   / BX 5450 Snow Thrower Reduction Gearbox Problem #3  
Moist chain drive chains have a removable link for disassembly, just like a bicycle chain. None in this one? Put one in.
   / BX 5450 Snow Thrower Reduction Gearbox Problem #4  
If the chain has repeatedly come off after the set screws loosens, I would suspect the chain is bent and should be replaced.
JWR's suggestion of drilling a depression for the set screw is a good one.
In the top right corner of the frame holding the shafts for the reduction box, a carriage bolt seems to be damaged or missing.
Dave M7040
   / BX 5450 Snow Thrower Reduction Gearbox Problem #5  
It looks like there is a master link on the right side just down from the top. But messing with a master link in those tight quarters could be fun.

How does the sprocket fit on the shaft. If it keeps coming loose the shaft could be worn. That might be part of the problem. I would replace the set screw with one as long as possible (but still flush with the outer diameter of the sprocket. Clean the set screw and sprocket so there is no oil to reduce the effectiveness of the locktite. Make a dimple for the setscrew on the shaft. Tighten it down and cross your fingers.

It might not hurt as you are doing this to loudly talk, saying you will take this apart again to check it before next snowblowing season. Nothing seems to make setscrew/sprocket combination freeze up tighter than the need to take it apart again. ;)

Doug in SW IA
   / BX 5450 Snow Thrower Reduction Gearbox Problem #6  
I just had the same repair this last week. I hit a paver and the chain derailed. The event also sheared the auger drive pin. (bolt)
The master link MUST be undone to get the chain over both sprockets!
Bit the bullet.
Detach the blower from the tractor.
Remove the shield.
Loosen the bearing support.
Use a paper towel or two to wipe the lube off the chain.
Locate the master link and roll it to the top sprocket.
Remove the link plate retaining clip with a common pliers. One jaw goes on the link pin and the other engages the open end of the clip. a squeeze releases the clip from the other link pin. The retaining clip may still hold to the other pin, so turn it 90 degrees to better see what it takes to get it off.
Remove the link plate from the pins. Push the Master link half through the two chain link holes. The chain is separated and may fall off the sprocket to the ground below.
Fix the sprockets as needed.

to reinstall the chain over the sprockets, it helps to twist a length of soft wire onto one end of the chain. Thread the wire down,around and back up over the sprockets. double check the chain is laying true on the sprockets. With both ends of the chain at the top, place the ends onto the sprocket and insert the master link half through the chain link holes with the removable link plate side out towards you.
Assemble the master link.
Lightly snug the bearing mount plate fasteners (4). adjust the chain tension not overly tight. rotate the entire blower mechanism looking for the tight spot in the chain travel.
Adjust chain tension, and tighten the mount plate fasteners.
lube chain
Install cover (2 cap screws)
Test rotation again! (don't ask me why ;-)
Refit the blower to tractor and give it a go!

It took me an hour.

I had thought to remove the bearing plate fasteners completely. I'm sure the chain could be fitted then. But there is no finger room to refit those lower carriage bolts. PIA! So no, I didn't go that way.

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