Self propelled gears not engaging

J

Jack9

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• Jul 31, 2019 / Self propelled gears not engaging

• #1

My Craftsman mower is rear wheel drive and has a Honda engine. It's about 6 or so years old. There are two metal gears that are supposed to mesh together to drive the wheels. One is a larger gear attached to the wheel hub. The other is a smaller one that is attached to the drive axle. The drive gear spins but is not engaging the wheel gear. The rear wheels are fairly new.

Again, these are both metal gears. This is not the typical problem people have where the metal drive gear wears out the plastic teeth that line the inner wheel rim. Mine doesn't have that type of system.

Does anyone know how I can get these two gears to engage?

 

M

mechanic mark

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• Jul 31, 2019 / Self propelled gears not engaging

• #2

have you disassembled & inspected other parts for wear or tried lubing or greasing assemblies? post your sears model number beginning with 917.

https://www.searspartsdirect.com/mo...aftsman-917374910-gas-walk-behind-mower-parts

 

Last edited: Aug 1, 2019

J

Jack9

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• Jul 31, 2019 / Self propelled gears not engaging

• #3

mechanic mark said:

have you disassembled & inspected other parts for wear or tried lubing or greasing assemblies? post your sears model number beginning with 917.

Click to expand...

I looked it over, including underneath, but didn't notice anything right off. I haven't greased anything as I don't see anything that could be.
The model # is 917.374910

 

R

Rivets

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• Jul 31, 2019 / Self propelled gears not engaging

• #4

Did you check to see if the pin behind the gear is still there or has fallen out? Pin drives the gear.

 

J

Jack9

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• Jul 31, 2019 / Self propelled gears not engaging

• #5

Rivets said:

Did you check to see if the pin behind the gear is still there or has fallen out? Pin drives the gear.

Click to expand...

You mean the drive shaft gear, correct? I'll check it, but wouldn't that make the gear not turn? Or does it keep it in place, which is why it might not be turning the wheel gear?

 

J

Jack9

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• Oct 3, 2019 / Self propelled gears not engaging

• #6

I guess I'll order new drive gears. I doubt they'll last very long though. The problem is they're too far from the wheel gear, which is how they ended up worn out to begin with, as there isn't enough contact area, and they're just riding on the the peaks of the gear. Then once it slips, it ends up grinding the gear down and making it even worse. I guess it's just a very poor design.

 

tom3

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• Oct 3, 2019 / Self propelled gears not engaging

• #7

Maybe a worn bushing or shaft that is allowing extra clearance between the gears? Or a slipped mounting point? Maybe flip that drive gear over and wear the other side? Looks like decent components with a poor setup.

 

dougand3

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• Oct 3, 2019 / Self propelled gears not engaging

• #8

The axle/drive gear sure is worn with that lower shelf. Only $6.32 on the sears site. https://www.searspartsdirect.com/mo...-917374910-gas-walk-behind-mower-parts?page=2
If the gear was the same on both sides, you could flip if over and wear down the high side.

 

tom3

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• Oct 4, 2019 / Self propelled gears not engaging

• #9

Just out of curiousity move the height adjustment up and down, see if the gears mesh improves?

 

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Jack9

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• Oct 17, 2019 / Self propelled gears not engaging

• #10

dougand3 said:

The axle/drive gear sure is worn with that lower shelf. Only $6.32 on the sears site. https://www.searspartsdirect.com/mo...-917374910-gas-walk-behind-mower-parts?page=2
If the gear was the same on both sides, you could flip if over and wear down the high side.

Click to expand...

I'm just afraid it will quickly happen again to the new gear.

You can't flip the drive gear because it has notches on one side that two pins that the drive shaft fit in that enables it to turn the gear.