QA-42A - blew up the input gear today

[mpatterson]

Well, I made it 3' in nice fluffy snow this morning. Didn't even get the 782 outta the garage door and it stopped.
Backed it inside and opened up the gearbox to find the input side, small 15T gear was in two pieces laying in the greasy mess in the bottom. I see Digger has new ones thankfully. Is there anything else I should be changing at the same time if this happened? It split right along the keyway of the gear. Just thinking preventative maintenance.??

 

[mfrade]

I'd think you'd be well served to remove it, tear it down and check all the shafts and bushings / bearings . Even the U-joints and the splined drive shaft, Hate to hear you were re-assembling it only to find more damage and then waiting for more parts. My 2 cents.

 

[mpatterson]

I'd think you'd be well served to remove it, tear it down and check all the shafts and bushings / bearings . Even the U-joints and the splined drive shaft, Hate to hear you were re-assembling it only to find more damage and then waiting for more parts. My 2 cents.

Good point. I'd be ticked at myself if that happened!

 

[bkattner]

Why do you think the gear failed? Did a stone jam the auger? Seems odd that it would break on its own.
I need to give mine some love but I've been needing it the last couple days.

 

[mpatterson]

Not sure? Weak over time??? There was barely any snow into the auger. Like I say, just leaving garage with it. No stones or sticks anywhere. Can turn auger freely by hand so its not binding anywhere, pto shaft seems to be good too. Head scratcher for sure!

 

[mfrade]

No one can say for sure but, it may have had enough play in one of the bearings to hit the lip at the garage door entrance or maybe it just got cocked or ..??..??..?? or maybe it just had enough hours of runtime?? That's why I thought it better to strip it down and see if there is any other damage or wear.

 

[mpatterson]

No one can say for sure but, it may have had enough play in one of the bearings to hit the lip at the garage door entrance or maybe it just got cocked or ..??..??..?? or maybe it just had enough hours of runtime?? That's why I thought it better to strip it down and see if there is any other damage or wear.

Agreed.

 

[mpatterson]

Ok, dumb question time...... when I use the part number off Digger's website for the 15T gear (IH-475604-R1) it comes up on the Cub website as being used in model CW36 model blowers. It doesn't list a QA-42A blower. Does that mean I have a gear box off a CW36 blower? I can't seem to find a listing on the Cub site yet for a 42A - so can't verify I have the correct gear box on the blower.
I opened up my tiller gearbox in hopes of it being the same - nope it has larger gears. Was hoping to do a swap to get me going in the short term.
So what size gears are supposed to be on a 42A?

 

[gpapa]

Can you post some photos?

 

[mpatterson]

Haven't cleaned up the output gear yet....

 

[digger]

Ok, dumb question time...... when I use the part number off Digger's website for the 15T gear (IH-475604-R1) it comes up on the Cub website as being used in model CW36 model blowers. It doesn't list a QA-42A blower. Does that mean I have a gear box off a CW36 blower? I can't seem to find a listing on the Cub site yet for a 42A - so can't verify I have the correct gear box on the blower.
I opened up my tiller gearbox in hopes of it being the same - nope it has larger gears. Was hoping to do a swap to get me going in the short term.
So what size gears are supposed to be on a 42A?

Gears are interchangable, the 15 tooth will make the thrower spin faster is all.

 

[digger]

Ok, dumb question time...... when I use the part number off Digger's website for the 15T gear (IH-475604-R1) it comes up on the Cub website as being used in model CW36 model blowers. It doesn't list a QA-42A blower. Does that mean I have a gear box off a CW36 blower? I can't seem to find a listing on the Cub site yet for a 42A - so can't verify I have the correct gear box on the blower.
I opened up my tiller gearbox in hopes of it being the same - nope it has larger gears. Was hoping to do a swap to get me going in the short term.
So what size gears are supposed to be on a 42A?

If you'll check the parts lookup, you find it uses the same gear.

 

[mpatterson]

If you'll check the parts lookup, you find it uses the same gear.
View attachment 141523

Ok, I couldn't find the QA-42A in the parts look up. That's where I was asking if I had the correct gearbox on my thrower. Hard to say how many people have owned this unit??
Thank you Digger!

 

[digger]

Ok, I couldn't find the QA-42A in the parts look up. That's where I was asking if I had the correct gearbox on my thrower. Hard to say how many people have owned this unit??
Thank you Digger!

 

[mpatterson]

View attachment 141524

yeah, I get this.
Search Results for QA-42A (cubcadet.ca)

 

[digger]

yeah, I get this.
Search Results for QA-42A (cubcadet.ca)
View attachment 141525

Use this site,
https://www.cubcadet.com/en_US/ari-partstream.html

 

[mpatterson]

Use this site,
https://www.cubcadet.com/en_US/ari-partstream.html

 

[rfunk]

Looks like both ends of the center part of the driveshaft are in the same plane. That is critical. Check and ensure! Also, if possible, post some extreme close-ups of the fractured area. It would be good to see if plain old fatigue played a part. Maybe sometime in the past, it was run "out of time" That would constantly shock load the driveline, and really eat into the lifetime. Lotsa lube, looks like good quality. My $0.02.

 

[hydroharry]

Mike - I'll be surprised if you don't find some other issue that could have caused the gear failure. I'm wondering if one of the internal snap rings failed allowing the gear to travel on it's own and not aligning with the large gear. Or maybe a bearing failed and wore one of the shafts causing a mis-alignment and the gear failure.

Also, you mentioned using the gear box off your tiller temporarily. It runs a 3:2 gear ratio and the blower has a 2:1 so I guess that means it would run a little slower. Might be worth a try but you'd probably need to install the speed up belt pulley.

And another thing. It's been a long long time since I tore into any of these gear boxes but I seem to recall the original outer bearings are only sealed on one side. The box uses a seal as a spacer on the inside of the bearing. This just seemed odd to me. The only grease the outer bearing gets is the little bit you can put inside the seal space when assembling. As such, when I replaced the outer bearings I used the type that have seals on both sides. You still have to use the seal in the parts list since it acts as a spacer as well.

The inner bearings are unsealed on both sides. They get grease from the oil/grease in the box. IH originally recommended using gear oil in the box and then later recommended using grease. I liked to use about half and half - and I think it's been discussed on here several times to use a mixture as well.

 

[mpatterson]

Well I removed the gearbox today and gutted it. Not good. 3 teeth off the large 30T gear as well. All the bearings are still in tact... but the two inside ones are growling at me, so I'm guessing that is what caused the breakdown as of now. NOT a cheap fix to say the least. The shaft seems to have a "burn" mark where the gear and bearing rode - so maybe it started to let go and then sat there to "burn" the shaft before breaking.????
Have to see if ordering parts or just scraping that gearbox and getting something different?? Looks like I'll be using the walk behind blower for a little bit.