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Discussion Starter #1
hi, I have a 6 H.P. 22" Rotary Lawn Mower- Mod. # 917.378060, Briggs mod. # 12H802, Type # 2640B1. The front wheels no longer turn when the belt is engaged. I put on a new belt, but that didn't fix the problem.

I was told to engage the front wheels with the engine off and if they wouldn't turn while the cable is engaged it means Trans. problem.

While engaged I can turn them manually, but they won't move on their own. There's a page in the owner's manual that shows all the parts inside the trans. box.

I can use a hand troubleshooting this problem if anyone knows this machine & trans.

Thanks.:confused:
 

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Probably a stripped gear inside the case, if your sure the engagement arm is being pulled back all the way and its not an engagement problem, then it sounds like a gear issue. Wouldn't be the first one.
 

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It's not uncommon for the helical gear to wear out on these gearboxes. Like justin referenced, if the engagement arm is getting pulled back and there is no engagement, then the problem is likely in the gear box.

They are not that hard to work on, and you can replace the entire gear box if you don't want to fix the one you have.
 

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Discussion Starter #4
It's not uncommon for the helical gear to wear out on these gearboxes. Like justin referenced, if the engagement arm is getting pulled back and there is no engagement, then the problem is likely in the gear box.

They are not that hard to work on, and you can replace the entire gear box if you don't want to fix the one you have.
Hi, I have a diagram of all the trans. parts. I see the Helical gear. I noticed there are 4 small bolts holding the trans to the chassis. If I pull the wheels & axles will the trans. pop off? When I get it open am I looking for a worn gear?

One note: If I engage the wheels with eng. off they lock up when trying to go forward. However, they don't lock up going backwards. Any other thoughts?

Hope things are good for you these days. Thanks.
 

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When engaged with the engine not running, the wheels should NOT turn, at least in a good gearbox. If they did turn this could indicate a problem with the control cable, or clutch jaw in the gearbox, or even a sheared key.

The problem most likely lies with the helical gear and possibly the worm gear as well. The only way to tell for sure is to have a look inside at the components.

Remove both wheels, then there are a couple of nuts on each pivot arm assembly on the back side underneath the mower deck. Take all 4 nuts loose, remove the drive gears from the axle shaft and the pivot arms will slide off. Disconnect the drive cable, remove the belt and release the tension spring from the gearbox and you should be able to slide it towards the long side of the shaft and allow the short side to drop out of the mower deck, then slide the other end of the axle out. Remove the retaining screws from the gearbox and split the gearbox open to reveal the internal components. You should be able to quickly discover the problem.

Best Of Luck.... :thumbsup:
 

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Discussion Starter #6
It's not uncommon for the helical gear to wear out on these gearboxes. Like justin referenced, if the engagement arm is getting pulled back and there is no engagement, then the problem is likely in the gear box.

They are not that hard to work on, and you can replace the entire gear box if you don't want to fix the one you have.
Hi 30 Year Tech, I took the gearbox out and opened it. The helical gear's teeth were all dished in the middle & I saw no wear in the worm shaft. I couldn't determine if the helical gear is supposed to have teeth that are the same height across or not as Sear's part site doesn't have a picture of the part. I asked the CSR if she knew, but she didn't.

Anyway I ordered the gear as it's only $7.50 + + = $15.00. I guessed that the gear's teeth should the same height across as it seems logical, but the way the worm shaft turns looked odd to me. If push comes to shove, I can return the gear if it's not the problem. Thanks.:confused:
 

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Discussion Starter #7
Probably a stripped gear inside the case, if your sure the engagement arm is being pulled back all the way and its not an engagement problem, then it sounds like a gear issue. Wouldn't be the first one.
Yes, it seems like the helical gear may be the culprit. Sears wants $82 for the entire gear box. That almost seems like a bargain if needed.:)
 

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Discussion Starter #8
When engaged with the engine not running, the wheels should NOT turn, at least in a good gearbox. If they did turn this could indicate a problem with the control cable, or clutch jaw in the gearbox, or even a sheared key.

The problem most likely lies with the helical gear and possibly the worm gear as well. The only way to tell for sure is to have a look inside at the components.

Remove both wheels, then there are a couple of nuts on each pivot arm assembly on the back side underneath the mower deck. Take all 4 nuts loose, remove the drive gears from the axle shaft and the pivot arms will slide off. Disconnect the drive cable, remove the belt and release the tension spring from the gearbox and you should be able to slide it towards the long side of the shaft and allow the short side to drop out of the mower deck, then slide the other end of the axle out. Remove the retaining screws from the gearbox and split the gearbox open to reveal the internal components. You should be able to quickly discover the problem.

Best Of Luck.... :thumbsup:
Hi 30 year, You were on the money- it was a worn helical gear. I have not seen a steel gear with a dished out center before. Sears must have used a softer steel for that gear as the worm drive was perfect. Thanks again. :thumbsup:
 

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Be sure to put plenty of grease back in the tranny box when you reassemble. I think they are a little stingy with the lube they put in from the factory, and this is generally why they fail.

Best of Luck... and Happy Holiday's!! :)
 

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Discussion Starter #10
Be sure to put plenty of grease back in the tranny box when you reassemble. I think they are a little stingy with the lube they put in from the factory, and this is generally why they fail.

Best of Luck... and Happy Holiday's!! :)
Hi, Actually, there was so much grease in the box that I had to scoop out a bunch to just see the guts. It also was black & worn out. I filled the gear box with new grease & the mower is running perfect.

Merry Christmas or whatever you celebrate this month and a Happy New Year. Walker:thumbsup:
 

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Glad to hear you got this one going again.

Merry Christmas and Happy New Year to you and yours as well.
 
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