Gearbox on Snowblower Questions

ollie770 · Dec 15, 2013

I just got a used 3 point snowblower and it needs some TLC. I want to change the oil in the gear box. If you look at the picture, there is a elbow and plug at the top (fill port). My question is about the 1/2 pipe plug on the side towards the bottom - is that the drain or the check plug? The very bottom of the gear box has nothing but the four bolts that attach it to the blower. Also is 80-90 gear oil the best the use?

Second question is the shear bolt flange that comes out of the gear box and drives the augers. Currently the hole for shear bolt is all cobbled up and sloppy. Someone has welding and tried to repair it. There is almost a 1/4 turn of slop. I am thinking easiest fix is quit using that hole and drill a new 3/8" hole on the other side of the flange?? Grade 2 or Grade 5 for the shear bolt?

ollie770 · Dec 15, 2013

Here is the shear bolt flange on auger drive shaft.

petetx · Dec 15, 2013

90 deg. fill port, 1/2 plug full level but looks like a hex plug at bottom for drain why not pump it full of crater o.

el6147 · Dec 15, 2013

the pipe plug on the side should be the level ( oil level for most gear boxes should be half or the center of the horizontal shaft ) try a grade two bolt first .

Anonymous-0 · Dec 15, 2013

Shear bolts are there to keep you from breaking your augur or your gearbox. They need to be fairly soft - harder is definitely not better.

ollie770 · Dec 15, 2013

Thanks for the replies. Thats what I was thinking but the square head pipe plug on the side is a little below center line.

JD Seller · Dec 15, 2013

I would clean up around the gear box and see if it is leaking. It sure looks like it is. If it is, I would drain all the oil out I could and then fill it with corn head grease. It will leak less when not in use but still provide the needed lubrication when being used.

If you have the time and knowledge remove the gear box an replace the seals. They are a simple gear case. The seals would be readily available by size. It would last you a life time then.

On the shear bolt. If you look the plates are thicker where the shear bolt is currently at. I would go 180 degrees and carefully drill a new square hole. Same size as the current one and use grade 2-3 bolts plus a lock nut. The thinner plates will wear out much faster if the bolt is allowed to loosen. Unless you are using it on a real big tractor you should rarely shear a bolt. I may have replaced one or two in ten years on mine. Those usually involves an ice chunk I should not have been blowing anyway.

ollie770 · Dec 15, 2013

On the corn head grease, do I fill it to the same pipe plug fill level or put more in? Thinking I would need to add a zerk where the fill plug currently is?

I can't tell if the "original" shear bolt hole had thicker material at the spot since it looks like someone tried to "fix" it with some weld. Think it would help to tack a thick washer on each side of the new hole to beef it up?

It is on an Oliver 1850 and its an 8 foot Snowmachines blower. I tried to find a manual or info online but found nothing on Snowmachines.

tiresntracks · Dec 15, 2013

I've worked on quite a few snow blowers, but they're a little bigger than yours. 85w-90 should work fine in your gear box. That's what we use, but it rarely gets down to 0* when we're blowing. If it gets colder, synthetic works good.
I would drill new holes for the shear bolt, if the flanges are soft enough to drill. When the holes get sloppy, you can shear the bolts just from the shock load when you start it. I don't like to use grade 2 bolts, because they stretch before they break, which will mess up the bolt holes. I've also seen them get stuck between the flanges and try to push them apart. Use a grade 5 and cut a groove around the bolt where the two flange halves meet. That will help it break cleanly and in the right place. The best way to do it is with a parting tool in a lathe, but a die grinder with a cutoff wheel while spinning it in a drill press works too.

jeffcat · Dec 16, 2013

Man you are not kidding. I have seen a couple of little snow blowers where some boob thought a regular bolt would work just fine. Shear pins are there for a reason!

Blackhole49 · Dec 16, 2013

I don't have anything that big but, I do have 4 different pieces of equipment with gear boxes. on all of them, the full level plug is below the center line of the horizontal shaft. I'm with Seller, go with corn head grease.

Gearbox on Snowblower Questions

ollie770

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ollie770

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petetx

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el6147

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Anonymous-0

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ollie770

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JD Seller

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ollie770

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tiresntracks

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jeffcat

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Blackhole49

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