# Craftsman 9.5 27" Snowblower - 2000s vintage



## glover_m (Oct 26, 2021)

Hey,

CRAFTSMAN
Part# C950-52361-0
9.5 HP 27 inch

I'm just wondering if anyone has any insight into servicing the auto lock clutch on a Craftsman snowblower (2000s vintage).

Engine fires fine, friction disc spins and rotates all internal chains. However the main drive axle is coupled to what's called an "auto lock clutch" and it appears that this isn't grabbing. This sprocket is physcially spinning but the inner rotation doesn't seem to lock with the outer sprocket and thus doesn't move the wheels. Does anyone have any ideas on fixing this? I have not opened it up yet.

I'm not used to seeing this in snowblowers so I'm not even sure if this is the problem... but it definitely seems like the point of failure to me right now.

Regards,
Michael


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## Oneacer (Jan 3, 2011)

So if I understand, you have drive to only one side?

i.e., the clutch feature is not working, allowing drive to the other side?

Is that even a serviceable part?

I would imagine there would be some type of ratchet/spring type slip differential, etc. in there ... ? Kinda what some earlier Ariens had.


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## glover_m (Oct 26, 2021)

Oneacer said:


> So if I understand, you have drive to only one side?
> 
> i.e., the clutch feature is not working, allowing drive to the other side?
> 
> ...


The inner "bearing or whatever" that couples to the left side axle and right side axle doesn't lock to the rotation of the sprocket. So I have no drive right now on ether side.. it kind of slips so it does move every once in a while but mostly the axles don't spin.

I'm nervous to open it up or grease/lube it cause I don't know if there'd be some kind of friction material in there. Just wish it was a simple sprocket! Why would they put a clutch on this?


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## Oneacer (Jan 3, 2011)

It is for ease of turning ... great feature, if the don't fail ... 

You already have it apart, .... if it was me, I would open it up and see what is going on .. it appears that once that toothed sprocket is removed, you would get a better sense of it, as maybe something stripped or broke in there ???


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## glover_m (Oct 26, 2021)

What do you mean ease of turning? Most newer snowblowers just have the axle coupled to the sprocket with no clutch mechanism and they work fine. Does this just make the wheels turn smoother cause it needs to get a certain rpm before engaging?

Hah I mean it does seem like I will have to do that. I originally thought it was a very simple sprag type clutch that would only allow the inner bearing to turn one way. Do you think that's how it shoudl work? Or does it need a certain amount of centrifigual force for the inner bearing to lock to the outersprocket rpm?


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## glover_m (Oct 26, 2021)

glover_m said:


> What do you mean ease of turning? Most newer snowblowers just have the axle coupled to the sprocket with no clutch mechanism and they work fine. Does this just make the wheels turn smoother cause it needs to get a certain rpm before engaging?
> 
> Hah I mean it does seem like I will have to do that. I originally thought it was a very simple sprag type clutch that would only allow the inner bearing to turn one way. Do you think that's how it shoudl work? Or does it need a certain amount of centrifigual force for the inner bearing to lock to the outersprocket rpm?


Oh derp, You mean that clutch/differential mechanism makes it physically easier for the user to turn


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## deezlfan (Nov 8, 2017)

If you would give us the actual model number, we may be able to look up the unit and find you some info on how they work or the common failure points. 

Not being familiar with this particular unit, I can't tell you how it is supposed to function but I certainly would be disassembling it. At the very least, there may be a way to disable it by drilling a hole through the sides and installing a bolt to lock everything together.


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## nbwinter (Jan 18, 2021)

Curious to see how you make out when it is open. I have never seen this. In the end you could just weld it together and not have to worry about it again.


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## glover_m (Oct 26, 2021)

nbwinter said:


> Curious to see how you make out when it is open. I have never seen this. In the end you could just weld it together and not have to worry about it again.


Hahah that's honestly what I'm thinking at this point!

Sorry @deezlfan, will upload the model # in a bit. I did a lot of reserach and only found one other post about this item (and it resides in a John Deere 1130SE blower). They had no advice. But I will post the information as soon as I can!


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## crazzywolfie (Jun 2, 2014)

if it currently doesn't work do you got anything to loose opening it up? i would guess based on the rivets on the side in the diagram is is a gear based differential but hard to say why you are having issues with it.


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## glover_m (Oct 26, 2021)

crazzywolfie said:


> if it currently doesn't work do you got anything to loose opening it up? i would guess based on the rivets on the side in the diagram is is a gear based differential but hard to say why you are having issues with it.


Wow that's an awesome photo. I will definitely take mine apart tonight. I'm curious as to why they would call mine an "auto locking clutch". Based on the photo you have here it is definitely just some sort of differential apparatus. But how does the outer sprocket cause the inner one to spin? That's what I'm confused by.


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## crazzywolfie (Jun 2, 2014)

probably because auto lock sounds better. it works just like the differential on a vehicle. as long as you are going in a straight line both tires spin the same speed but when taking corners 1 tire spins slower as the other spins a bit faster. some machines


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## glover_m (Oct 26, 2021)

deezlfan said:


> If you would give us the actual model number, we may be able to look up the unit and find you some info on how they work or the common failure points.
> 
> Not being familiar with this particular unit, I can't tell you how it is supposed to function but I certainly would be disassembling it. At the very least, there may be a way to disable it by drilling a hole through the sides and installing a bolt to lock everything together.


CRAFTSMAN
Part# C950-52361-0
9.5 HP 27 inch
Dual Stage Snow Blower


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## HCBPH (Mar 8, 2011)

I've never seen anything like that before in a snow blower. If you don't mind having 2 locking axels instead of turnable ones, here's an old drag racer trick: weld it up to make a solid hub out of it. Drag Racers have done that for years so both tires will always turn as a pair.


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## glover_m (Oct 26, 2021)

Here is what the internals look like. I see no springs just rollers and some rubber circles in between the pieces. There are basically two sides to this similar to the other differential posted above. I oiled everything up and things spin better but not even sure how the rotation of the sprocket causes the inner pieces to spin. Science... how does it work.


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## crazzywolfie (Jun 2, 2014)

i am not sure how that one would works but i have a feeling that piece that looks broke in the picture may be why it is not working as it should.


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## glover_m (Oct 26, 2021)

crazzywolfie said:


> i am not sure how that one would works but i have a feeling that piece that looks broke in the picture may be why it is not working as it should.


Its just a thin piece of rubber. I didnt think that would cause it not to work?


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## crazzywolfie (Jun 2, 2014)

oh. if it is just a piece of rubber that shouldn't cause it. really hard to say what might be causing the issue without tearing it apart to see how it works. does that rubber piece come off easily enough to get a picture of what is under it?


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## Tony-chicago (Feb 10, 2021)

Interesting. Need to see this.
Is that yours opened up. Title lists it as from a wooden bicycle.

It may be a death by a thousand cuts situation.
Try to picture how it would work if the power were input from the axle. Then the reverse. I get a bit but it seems there is something broken. How heavy duty is that "rubber" ring?


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## Tony-chicago (Feb 10, 2021)

Wonder if the ring is the slip joint in this scenario. Looking for info online is not helping.


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## glover_m (Oct 26, 2021)

Just a follow up guys. So I ended up taking apart that differential and I think the rubber rings are worn or something. I ended up basically fusing it all together by putting some washers in the middle of it. Now the wheels are locked. I could probably have maybe fixed the rubber rings which basically cause the inner bearing to lock to the outer sprocket, but it didn't seem worth the effort. I imagine that - as someone mentioned earlier - it's probably easier to turn or use if you lose traction on one wheel. However considering most snowblowers nowadays are all made with locked differential, I think this setup will suffice.


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## Oneacer (Jan 3, 2011)

I would assume in its original state, it would have operated like a limited slip differential.

Most snowblowers now-a-days are actually going to some form of zero turn or slip differential. I personally like the slip differential, as it usually requires no operator control.

You can certainly lock the axle into direct drive to both wheels, just makes turning tight a bit getting used to.

A lot of blowers simply pull a wheel pin and place it forward of the wheel in a separate hole, thus allowing one side to free wheel.


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## glover_m (Oct 26, 2021)

Oneacer said:


> I would assume in its original state, it would have operated like a limited slip differential.
> 
> Most snowblowers now-a-days are actually going to some form of zero turn or slip differential. I personally like the slip differential, as it usually requires no operator control.
> 
> ...


Interesting. Yeah I thought new blowers were mostly just locked differential... good to know. Yeah I mean I would have liked to keep the differential but when I took that thing apart it was pretty clear the rubber rings that basically push up against the housing were pretty worn. Like they didn't even touch the outer sprocket so they never had any friction to grab. I think I'll try to run this as is for now and if it becomes annoying to steer then maybe I'll dig into it again!


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## glover_m (Oct 26, 2021)

One thing I wanted to add: in this differential mechanism I didn't see anything which would push both halves of the differential apart like a norma limited slip differential does. So I'm kind of confused what force actually causes the inner bearings to push away from each other and rub against the outer sprocket and lock in place. That's kind of why I put the washers in there... so I basically forced the two halves apart from each other so they have friction up against the outer sprocket. I'm not sure if a piece is missing or somthing inside... but there definitely wasn't any springs.


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## Tony-chicago (Feb 10, 2021)

After a few days learning as much as I could about these differentials, I know less now.

One way to approach it is to think of it from the axles/wheel as the power input, and the differentials that will change. Other than the rubber parts I got no where.


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## Oneacer (Jan 3, 2011)

Looks like a lot of wear against the outer case, but I would imagine when it was new, the round rollers are in an oblong casing, using that as pressure source. Would have to see a new one or the specs to confirm.


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## Tony-chicago (Feb 10, 2021)

Agree. The wear on the rollers, and what appears to be a joining or so.


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