# troy bilt 2840 thumping sound



## slfalco

Hello. I just had the misfortune or running over an unwanted phone book that some moron decided to deliver by throwing it on the end of the driveway just before 8 inches of snow. One of the shear pins broke, which I replaced. But now I hear a rhythmic thump sound when engaging the auger, which occurs a little less than once per second.. I don't see anything that the augers could be hitting... Could the gearbox be damaged? Is there an easy way to spin the auger slowly to try to isolate where it is coming from (unhook a belt perhaps)?


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## motorhead64

SL,
Check your auger belt. Chances are, brief ore the pin sheared, the belt lost some plies. It is thumping when the thin part passes the pulley. MH


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## Shryp

I would check the belt, but once per second sounds more like augers to me.

You can turn the impeller by hand, but the brake will drag a bit making it a little difficult. Make sure the engine is off first and it also doesn't hurt to disconnect the plug wire. You might be able to hold the handle down far enough to release the brake without engaging the belt if you are lucky. Easiest way to really get a good look at the front end would probably be to remove the front scoop from the blower, but that can be time consuming.

While checking things out make sure the auger shafts are still in the outside bushings. Those can pop out easy when you hit things and it spreads the sides of the shell out. Only way to fix that if they are spread is to pull the impeller, augers and gearbox out the front and then bend it back in for a nice tight fit.

Sounds as if you you have one of those newer style MTD blowers that has the 2 thin stamped auger pieces on each side with the plastic bushings between them. Those look like they will bend real easy so take a close look through their whole rotation. Also, check for fresh scratches in the paint to find rub marks.


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## slfalco

Thanks for the suggestions. There are 4 seperate augers, with plastic bushings in between. I will remove all the shear pins and spin the augers by hand to make sure they are not hitting anything, and also check the ends of the shaft to make sure it did not come dislodged on either side. How sturdy is the gearbox in these things? metal gears?


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## Shryp

The impeller shaft is steel and the auger gear is brass. They do break fairly easily. Either the teeth all get ground off or if the impact is severe the gear can crack.


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## Kiss4aFrog

The is always a chance the auger shaft itself is bent but not enough for the augers to hit the housing. Did the book end up wedged between one of the augers and the housing ??


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## Shryp

If the shaft is bent you would be able to see some movement if you watched them spin from in front of the machine.


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## slfalco

I watched the shaft while standing in front, did not see any noticeable bend to it. I will look more closely this evening.. If it is damage to the gears, am I looking at a pricey repair? Can the gears be replaced, or is the whole gearbox replaced as a unit? A chunk of the phone book was wedged in there as I recall. but the auger that had jammed had the broken shear pin... Assuming no bent shaft, or the augers hitting anything, I guess the gearbox is the only thing that could be making that noise... I'll post again tomorrow...


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## Shryp

Usually it is just the brass gear. Sometimes the impeller shaft gets damaged too. While you have it apart inspect the bushings and everything to see if anything is worn. If you just need the brass gear most MTD ones are around $35. Some of them are around $55. Other brands can be close to $100 for just the gear.

You will need some "00" grease or something for the gearbox. I think that is what is in yours, but some use regular 85w90 gear oil like a car. Either of those can be had for around $10 per quart. You can get smaller tubes cheaper since you only need a tiny bit.

If you really think you have an issue the first step would probably be disassemble the bucket and see if the gearbox turns smoothly in both directions with no stepping or slipping.

Have a look here and see if it helps:
Rebuilding an MTD snowblower auger differential - Tool Shed Forum - GardenWeb

Also these:


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## slfalco

OK, after pulling all the shear pins and rotating each auger, I found one of them was bent and hitting the housing (oddly, not the one where the shear pin snapped, but the one next to it). After some precision re-adjustment (bending with big a$$ pliers), things are all good. Thanks for all the suggestions.


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## Shryp

Glad it is fixed. Either that one caught part of the book or it hit the other one after it broke.


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