|How To: Rebuild
Honda Snowblower Transmission
My Honda HS928 Snowblower has been through 11 Newfoundland winters, and racked up a heck of a lot of hours. I never just clean my own driveway, I love to help neighbors especially after a major storm so my blower has quite a few hours on the clock. It's a known problem with these units for the track drive Transmission to fail leaving the machine motionless.
The drive system consists of a Hydrostatic Oil Pump which is controlled by the lever on the control panel. Power is fed to the tracks through a gear case which is grease filled and not sealed 100%. There is a grease fitting behind the right side track that isn't listed in any service literature for these machines. Greasing this fitting regularly will extend the life of these gear cases.
Most people make this repair after the blower breaks and stops moving. I inspect my machine regularly and noticed that there was a lot of free play in the tracks. I could move the machine forward & back 6" by pushing/pulling. Also the drive shaft that attaches to the white cogged wheels had a lot of up/down movement at the gearbox, a sure sign of failed bearings.
I began disassembly by turning off the fuel switch, draining half of the fuel from the tank and all of the fuel from the carburetor, then rolling the machine up on the bucket and tying it to a wall anchor.
I removed both tracks & wheels by loosening the adjusters and pulling the outer pins. Take pictures of all the spacers and washers behind the wheels so you can easily reference them during reassembly.
I pulled the top pin for the height adjuster piston, loosened the track adjuster bolts, removed left & right crawler frames, and rear crawler axel then swung the remaining piece attached to the piston up and out of the way.
The outside cover of the gearbox is actually the Right Side plate of the Snowblower frame. Remove the rear & bottom skid plates, all the 12mm bolts holding the side plate to the bucket (there is one on top which necessitates removing the Headlight Bracket and plastic Belt Cover), and finally the 10mm bolts that attach the side plate to the gearbox. These are nuts and bolts so be careful not to loose the nuts. I pressed all my bolts into a diagram drawn on a piece of cardboard to make sure they were all accounted for during reassembly. I had to fight with two of the 10mm bolts, they were over torqued from the factory and stripped the threads off the bolts as I removed them, luckily Honda One had replacement bolts in Stock (the broken ones were a specialty bolt with an extended collar)
The inside of my transmission was extremely dirty. Other's I've worked on that haven't been greased over the years have very little factory grease remaining.
The repair kit from Honda One includes a new track drive axel, the big lower gear (described as in the pic above), the smaller of the two middle gears, the countershaft that both middle gears run on, all new bearings, plastic bushings, and a paper gasket. Their parts list also include a bearing for the driveshaft where it goes through the left side frame, and two crawler bearings behind the white drive cog wheels.
To remove the gearbox I removed the top gear and hammered the track drive axel from the opposite side as it was stuck in the bearing races. Sometimes you have to cut the old drive axel in two and unbolt the left side bearing retainer from the frame to make the job much faster. Don't forget to disconnect the return springs for the belt tensioner as they attach to a bracket bolted to the back side of the gear case.
Gearbox removed, the hydrostatic pump remains in place as its in great shape and not leaking. If you ever decide to change the hydrostatic fluid (which Honda states is good for the life of the machine) this pump has to be removed and bench bled following a very thorough procedure.
The bearings were a PITA to remove because they were rusted and seized in place. The top and bottom bearings can be hammered out from the back side of the gear case using a steel punch against the inside race. On my blower the lower bearing came out in pieces leaving the outer race seized into the gear case. I had to very carefully cut a groove all the way through the steel race but not into the aluminum gear case, then I used a small flat chisel and hammer to loosen and eventually split the race.
The middle bearing can be difficult as the case has no access hole on the back side of the gear case. On other machines I've drilled two small holes right behind the outer bearing race and popped out the bearing using a small round punch. I recently received a new tool called a blind bearing puller & slide hammer which should make these jobs much easier.
On my blower the Countershaft was seized solid in the middle bearing and would not come out. I drilled a small hole on the back side of the gear case directly in the centre and popped out the post & bearing all at once using the same small round punch.
Once cleaned I fill any drilled holes with automotive gasket maker.
The gear box and all reused parts were thoroughly cleaned in my parts washer.
Next new bearings were pressed in place. In the top of this pic you can see where the track drive gear was rubbing the aluminum case. Most people let this go for so long that the gear wears clean through the aluminum housing meaning it also has to be replaced.
The kit includes new bearings for the left and right crawler plates and for the frame bearing pictured in the centre above. I replaced all of these with the included parts even if the old bearings were not too bad. The gearbox was refilled with appropriate grease coating every piece then filling the voids in between and reinstalled on the machine. Don't forget to install the new paper gasket on the gear case, a little grease will hold it in place. When you install the gearbox cover/right side plate install a couple 12mm bolts to hold it secure to the bucket, then there are two 10mm bolts with a collar. Install these first as they align the gear case with the side plate perfectly.
With all the bolt reinstalled, and return springs for the belt tensioners reattached to the gear case, install the new drive axel gasket which goes over the drive axel onto the side plate behind the right side drive wheel. The rest of the machine was reassembled in reverse order.
The old parts were in pretty hard shape, the kit from Honda One is perfect in that it replaces everything you need while retaining a couple of the gears that were OK.
I got my machine back together just as the first Blizzard of the 2017-2018 Winter season arrived
Copyright © 2011 Michael Smith