# Why Would Teeth Shear In A Recently Serviced Right Side Tranny?



## orangputeh (Nov 24, 2016)

I recently purchased a really nice HS928 that had a skip in the right side tranny.

Opened it up and the grease looks very new. It's clean inside the the case and this machine is at least 10 years old. Not really sure yet but going by serial number. 

The main gear that is on the drive axle with pin has 4 teeth sheared off. they are sheared off completely on one side and not so much on the other as if the gear was slipping out from the other gear and got jammed for some reason. I took the gear case apart and everything is present as it should be. spacer washers and the final drive bushing was fine.

so I am wondering how this happened? i can not get a hold of the guy I bought this from to ask him if he had recently had the right side tranny serviced/repaired. Most likely repaired and then for some reason the gear broke.

Wondering what i should inspect. I would hate to put new gear in and have this happen again?

The machine is clean. the axle is clean. the bearings I will inspect. at first I guessed something was missing so the gears would not mesh correctly but all the parts are there.

any ideas? or experience with this? what should I check if all bearings are good and all parts are there? totally fresh grease as if this was just done.

By the way , nothing was loose when i took it apart


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## contender (Jan 18, 2018)

Unless, you familiar with the seller, I suspect if its a clean as you say inside the right tranny and you did not find any of the four teeth, it was reassembled the way you found it. You should be able to tell, if it matches the other drive gears in colour and texture or has been thrown in to sell. My experience, but not the hundreds like you have serviced, tells me the bearings and bushing usually fail, causing the gear wink to open up to allow things to start jumping teeth....just my 3 cents.....

Unless the wrong gear or gears were used....


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## orangputeh (Nov 24, 2016)

contender said:


> Unless, you familiar with the seller, I suspect if its a clean as you say inside the right tranny and you did not find any of the four teeth, it was reassembled the way you found it. You should be able to tell, if it matches the other drive gears in colour and texture or has been thrown in to sell. My experience, but not the hundreds like you have serviced, tells me the bearings and bushing usually fail, causing the gear wink to open up to allow things to start jumping teeth....just my 3 cents.....
> 
> Unless the wrong gear or gears were used....


i understand what you are saying . the bearings are all in new condition. I found 3 of the 4 teeth. the bushing was slightly malformed. that may be something. I have serviced many Hondas but this is only my 5th right side tranny/repair.

I did find that this outside pin was missing. this the the pin that stops the bearing on the side plate. wondering if that could cause enough axle play to cause a problem. the plate was tight as well as the pedal.
It just seems like this was just done as everything came apart real easy. All the bolts / nuts / threads were clean.

the second picture shows the other side and pin that stops the bearing/plate for reference.


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## contender (Jan 18, 2018)

First off, I personally don't try to service the right transmission without removing the right hand black side plate so I can pull the drive shaft clear of the rest of the machine. 

I would start by taking the first 3 digits of the S/N and confirm you have the correct gears in there, ie the final big one, 48T or 38T. 

My experience is if the shaft can move sideways it takes the pin out or just doesn't try to drive. Just my 3 cents

Has the famous shaft pin been replaced?? One side appears longer than the other as if someone has drill the shaft and replaced the pin with a cutoff drill bit or something. As well the pin ends are normally rounded off, not cut square as those appear to be....


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## orangputeh (Nov 24, 2016)

contender said:


> First off, I personally don't try to service the right transmission without removing the right hand black side plate so I can pull the drive shaft clear of the rest of the machine.
> 
> I would start by taking the first 3 digits of the S/N and confirm you have the correct gears in there, ie the final big one, 48T or 38T.
> 
> ...


ok. good tip. i'll check the serial number and make sure i have the right gears . the broke gear is 48T . The inside pin looks normal to me. I'll have to clean up everything better.


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## contender (Jan 18, 2018)

OK, guess I am misseeing, but your pin in your picture appears to be different lengths on one side than the other as well as having squarer shoulders on the ends of the drive pin. Why is the shaft so black around the pin, does it show signs of being heated??

Here is a brand new original shaft for a HS928 after frame serial 1120842, notice the rounded pin ends....I have never seen a original Honda shaft that doesn't look like that, unless of coarse its broken.....P/N 23370-767-020.
Maybe Honda ships different shafts, north of the border??

How many teeth does the matching gear have??


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## orangputeh (Nov 24, 2016)

contender said:


> OK, guess I am misseeing, but your pin in your picture appears to be different lengths on one side than the other as well as having squarer shoulders on the ends of the drive pin. Why is the shaft so black around the pin, does it show signs of being heated??
> 
> Here is a brand new original shaft for a HS928 after frame serial 1120842, notice the rounded pin ends....I have never seen a original Honda shaft that doesn't look like that, unless of coarse its broken.....P/N 23370-767-020.
> Maybe Honda ships different shafts, north of the border??
> ...


Man, you have some eagle eyes. I looked at the axle and no hole was drilled but the pin is longer coming out one side than the other.( by about 1mm or so) I have that same axle as you from boats.net.( in bag ) same number . it is tapered also but the other right side trannies I have done all had squarish heads like this 928.

but the pin is about 4-5 mm shorter than the one on the 23370-767=020 shaft. I wish i had a used axle handy to compare. 

the matching gear also has 48T


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## contender (Jan 18, 2018)

Guess, I misspoke, but I was asking how many teeth that the gear has that meshes with the gear with the broken teeth??

What's the black stuff near the pin and what are the first 3 digits of your S/N?? there are 2 different generations of the final drive gear set...


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## contender (Jan 18, 2018)

When you service the right transmission case , do you install the 2 grease fittings?? 

Do you also replace the small bushing p/n 23222-767-A11, that supports the counter shaft?? I have seen a few rebuilds that don't include that bushing....


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## orangputeh (Nov 24, 2016)

contender said:


> Guess, I misspoke, but I was asking how many teeth that the gear has that meshes with the gear with the broken teeth??
> 
> What's the black stuff near the pin and what are the first 3 digits of your S/N?? there are 2 different generations of the final drive gear set...


not sure what black is. i cleaned it but still some black. the serial is SZAS1111400 so it's an earlier. the shaft I have is for an 1132 that I am also redoing. 

the gear you are speaking of has 19T and it looks perfect. no damage


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## contender (Jan 18, 2018)

When you slide your large broken gear over the pins on the shaft, does it slide on all the way?? Maybe that is the old style and the pins had the flat ends like you have but if there is a difference of 1mm in the length of the pin between the 2 sides I would be surprised if it fits to the bottom of the cutout in the gear. Try it one way and then rotate 180', does it still bottom out??

Sorry , I don't have a example of the first generation in stock at this time.


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## orangputeh (Nov 24, 2016)

contender said:


> When you service the right transmission case , do you install the 2 grease fittings??
> 
> Do you also replace the small bushing p/n 23222-767-A11, that supports the counter shaft?? I have seen a few rebuilds that don't include that bushing....


I only install one grease fitting. where do you place them?

Yes, I replace the bushing with a new one. that was my original thought . that the bushing was damaged or missing so as to allow too much play so gears would not mesh correctly but this was not the case.


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## contender (Jan 18, 2018)

One fitting on the top corner of the case above the neutral swing lever and the other if not already installed is on the outside of the lump that holds the above mentioned bushing. In Canada, I have seen it on HS724s, HS928s and mostly on HS1132s, factory installed. So now when I service a right transmission, it doesn't go back together until both are added.

Report back on how the broken gear engages the pin on the shaft....please


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## orangputeh (Nov 24, 2016)

contender said:


> When you slide your large broken gear over the pins on the shaft, does it slide on all the way?? Maybe that is the old style and the pins had the flat ends like you have but if there is a difference of 1mm in the length of the pin between the 2 sides I would be surprised if it fits to the bottom of the cutout in the gear. Try it one way and then rotate 180', does it still bottom out??
> 
> Sorry , I don't have a example of the first generation in stock at this time.


yes it does slide on the way and is supposed to be a little shorter than from 112 on. I tried that gear on my new shaft and it does not fit. 

i tried it both ways and it goes all the way on but does have a little wiggle from side to side. I wish I had another shaft to compare. the other shafts all had broke pins. the other services I did were 2 828's, 0ne 928 and one 1132 and they all had the shorter pin with the squarish heads ( if memory serves me right )

none of those pins were broken. I just wanted the practise of doing it and putting in new bearings, bushing and grease. 

I wondering why the 19t gear looks perfect with no damage if the 48T gear sheared 4 teeth with the remnants in case.? could this happen if operator tried to force the tranny in a jam? I have seen people slamming their blowers at a berm at full speed and then getting jammed up. I cringe . 

they probably all broke at the same time . the 3 broke pieces I found are all the same size.


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## contender (Jan 18, 2018)

Do you have any history on the seller?? Was this one of you free EOD finds on your drive arounds. 

You suggest that that's the way you got it, so I question its history. I still question the looks of that pin and the black shaft, to me it looks like torch marks...
I bet that pin can be driven so both sides stick out the same amount??

With a little luck I may get to test my HS621 Sat or Sun morning, according to the weather lady!!!!


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## contender (Jan 18, 2018)

BTW, a close up pic of the gear set for your early s/n, 04201-767-000, also shows the pin having tapered ends.....


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## orangputeh (Nov 24, 2016)

contender said:


> Do you have any history on the seller?? Was this one of you free EOD finds on your drive arounds.
> 
> You suggest that that's the way you got it, so I question its history. I still question the looks of that pin and the black shaft, to me it looks like torch marks...
> I bet that pin can be driven so both sides stick out the same amount??
> ...


I bought it from an older gentleman that did not give me any history on the machine. As mentioned it is pretty clean for what I believe is an early hs928. The bearings, grease looks fairly recent. there is no rust anywhere and it all cam apart in about 15-20 minutes. a new record for me and I was not in a rush.

I'll clean everything up real well tomorrow and try to find that last tooth. I already triple checked that all the washers are there . I can also inspect better the counter shafts for any damage.

thank you for all the help and patience. I'll report back with any new info. 

good luck on that weather coming in.


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## contender (Jan 18, 2018)

No Problem


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## tabora (Mar 1, 2017)

Boy, I'm glad I jumped from the HS80 to the HSS1332 and missed out on all this right-side transmission drama! Still fascinating to follow, though...


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## contender (Jan 18, 2018)

Tabora, actually, a guy with a grease gun, could keep any of the right transmission machines going for years if he didn't abuse them. A commercial guy the same if he just thru some grease at them once in a while. I never used an 80, but my favorite Honda dealer salesman(jack of all trades) , still uses an 80.

The machine we have been discussing is pre 2002 IMO, I have a 2002 and his number is older than mine. Between our two serial numbers , Honda changed the gear sets and I only have experience on the later ones.

Its a great design but does need some grease from time to time......enjoy, play safe....

P.S., Are you getting any of the rain or flooding that's hitting parts of Ontario as well as the eastern Provs??


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## contender (Jan 18, 2018)

Orang, Your serial is 111XXXX, mine on my HS924 is 1135xxx and was retailed in 2002, so that should give you a ball park of the age of yours. Mine also uses the later gear set....


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## tabora (Mar 1, 2017)

contender said:


> P.S., Are you getting any of the rain or flooding that's hitting parts of Ontario as well as the eastern Provs??


We have heavy incoming as I type... Supposed to get 2"+ and hope the dam holds!


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## orangputeh (Nov 24, 2016)

tabora said:


> Boy, I'm glad I jumped from the HS80 to the HSS1332 and missed out on all this right-side transmission drama! Still fascinating to follow, though...


My 80 is still my main machine. Something breaks in those final drive gearboxes as well but i don't think it's a pin. a dealer told me it is usually a stripped spindle .that the gear is attached to. and those are no longer available from anyone except some sellers on ebay.


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## contender (Jan 18, 2018)

Tabora, You still come up to Mississauga to shop sometimes?? I'm 45-50 mins west of that and north of the 401.

You must be near the bottom of Maine, is that fair??


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## tabora (Mar 1, 2017)

contender said:


> Tabora, You still come up to Mississauga to shop sometimes?? I'm 45-50 mins west of that and north of the 401.
> 
> You must be near the bottom of Maine, is that fair??


 I used to get up that way every couple of years, especially when I had an office & apartment in the metro-NYC area, and we also had a sister organization (Konica Canada) in Mississauga... Mostly go up towards Montreal/Quebec City/Maritimes now. We'll probably head back up to The Falls within a few. Always enjoy the view. 

Yes, I'm far enough down in Maine that it's practically a suburb of Boston, but I have a place in Waterford and my wife has a family place on Vinalhaven, so we get around the southern end of the state quite a bit. It actually takes me an hour longer to drive to the northern tip of Maine than it takes me to drive to NYC. 

I try to go up to the northern counties to hunt, fish, canoe and kayak every year. My best friend takes a fly-in canoe trip to Labrador every year and he's always trying to get me to go along and act as bear bait, but so far I'm still holding out for an arctic trip...


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## contender (Jan 18, 2018)

Over to PM


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## ST1100A (Feb 7, 2015)

Those gears don't always match up perfectly. They are designed to have side to side play to accommodate warping and chassis flex which is normal.
Those gears most likely snapped when the operator engaged the drive handle with the transmission lever in the full forward position causing the sudden "Shock" to the gear train, and a lot of stress on the first gear tooth to break, then like a "Domino Effect", it took out a few more gear teeth. Something extremely common in the "Motorsports Industry".
The operators manual tells to start out at the lowest speed setting, then when it is engaged and moving, gradually increase speed to prevent the type of damage you have experienced.
The gear teeth will break a lot easier than the pressed in pin in the axle and gear shafts due to the materials used in manufacturing.
Most gears are "Sintered" not "Billet", or cast steel which is brittle to a point and will fracture and snap or break the teeth off quicker than the pin in the axle or gear shafts.
That happens a lot with inexperienced operators, they start out with it set in the "Fast" position instead of starting out slow and working their way up. They are usually in a hurry to get the job done.
If you ever had an automobiles clutch apart, you would notice the "Damper Hub" in the center of the hub where the transmission shaft slides into, that is to prevent the type of damage to the gear teeth and the rest of the drive-train in the auto. Snowblowers don't have that type of damper in their drive-trains, that would add extra cost and weight. Motorcycles have "Dampers" built into their clutch hubs on street bikes, the race bikes don't have the dampers in theirs. They expect to blow transmissions apart, that's part of the sport.
Also by engaging at full speed, the sudden shock to the drive-train and gear case, it can cause the gear case to actually move a little bit where its mounted to the frame from the torque generated in it, causing it to twist around a little bit. It can cause the mounting bolts to stretch a little and loosen up a bit, and also with the case moving or shifting its position a little bit, that will keep the gasket from sticking fast, making dis-assembly a lot easier. I see that happen with tractor transmission cases on occasion.


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## groomerz (Feb 7, 2015)

We use the 928 in commercial snow removal and broke 1st month of use. It is from engaging drive at full speed. Operator error Was told to lower air pressure in tires to absorb the shock. Honda shouldn’t have put speed control on left side of console as you have to use right hand and reach across console to operate. 


Sent from my iPhone using Tapatalk


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## ST1100A (Feb 7, 2015)

groomerz said:


> We use the 928 in commercial snow removal and broke 1st month of use. It is from engaging drive at full speed. Operator error Was told to lower air pressure in tires to absorb the shock. Honda shouldn’t have put speed control on left side of console as you have to use right hand and reach across console to operate.
> 
> 
> Sent from my iPhone using Tapatalk


They had to do that because of the chute control cable, so as to keep it away from the muffler, so they mounted it on the right side, and kept the drive control on the left side. They figured people would just reach over to the left for speed and direction, right for turning the chute and raising and lowering the chute deflector, at least they kept those two together.
They kept all of your drive controls, wheel engagement, plus speed and direction on the left, and all of your auger controls, engagement, and chute direction controls on the right.
They kind of built it for a "Right Handed" person. You keep your left hand on that control lever to keep both interlocked and engaged, and use your right hand to do everything else. I would imagine some "Left Handed" people might have a little bit of trouble working with it if they are not "Multi-tasked" too well, and now you see some newer bigger models with electronic controls or Joy-sticks for chute controls to make that part easier so they don't have to reach around as much.


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## orangputeh (Nov 24, 2016)

ST1100A said:


> Those gears don't always match up perfectly. They are designed to have side to side play to accommodate warping and chassis flex which is normal.
> Those gears most likely snapped when the operator engaged the drive handle with the transmission lever in the full forward position causing the sudden "Shock" to the gear train, and a lot of stress on the first gear tooth to break, then like a "Domino Effect", it took out a few more gear teeth. Something extremely common in the "Motorsports Industry".
> The operators manual tells to start out at the lowest speed setting, then when it is engaged and moving, gradually increase speed to prevent the type of damage you have experienced.
> The gear teeth will break a lot easier than the pressed in pin in the axle and gear shafts due to the materials used in manufacturing.
> ...


Thank you for this explanation. I was thinking it was this or the machine was jammed and the operator just tried to "force" it. I inspected the case and gears etc. very thouroughly and everything was present. The final drive bushing was slightly warped and the other small bushing that is pressed into the side cover was missing about a third of it's rim.

The final gear was missing 4 teeth but i could not see any damage on the meshing gear or counter shaft. Not sure if this machine was recently serviced in this area but the grease was very clean and the bearings looked new . Everything was very easy to take apart and this is an early 928......1998-2001 thanks @contender 

I did mention that the stop pin was missing on the axle shaft as I showed where that is located in the pictures. I think that pin is to stop movement of the side plate ? I'm not sure if this could have contributed to excess play of gears in gearbox.

I'm thinking that it may just have been operator error. I replaced the gear and bushings and am going to put back together and test it soon. unfortunately my wife has a very strict rule about working on Sundays. She said I have to take her somewhere like a ride or shopping or something like that. at the very least spend time with her.

I don't get that. We have been together 35 years. don't know why she wants to spend time with me.......


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## ST1100A (Feb 7, 2015)

Hi OP, 
That sure sounds like operator error. The previous owner was engaging the drive with the tranny set at full speed. That sudden shock will break teeth and cause the wear in the bushings you described, almost like taking a hammer to it, I.E. the axle/gear shaft beating against the bushing, causing it to distort/oblong/oval itself out, caused by the torque roll to the gear shaft. Almost like the wear in a connecting rod bearing when an engine is run without oil.
Once it gets "Out of Round" you will have a lot of damage because it will concentrate all of its pressure right in that spot instead of spreading the pressure out around the bushing.
Good luck with your repair, it should work out well once you are done with it, and not give you any more problems. Take the day "Off" and enjoy yourself, I know how you feel, you want to get it done first, then enjoy yourself with the family.
Hopefully we wont need them soon, and start playing with "Lawn Mowers" until next season.


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