#450 Snowblower Gearbox Removal?

[aaytay]

It looks like the gearbox on my #450 snowblower may have coughed up it's gears today.

If anybody has any tips on how to remove the gearbox, I'd love to hear them. It looks like just a few easy bolts, but how does the lower shaft disconnect from the 2nd stage "fan" inside the housing of the thrower? (Maybe the roll-pin needs to be driven out of the fan..?)

 

[jdiederichs]

Art,

Which gearbox failed, the primary one or the worm gear that drives the auger? If it is the auger gearcase, the best method is to remove the auger support bearings at each end, remove the auger gearcase support bracket in the center of the blower housing, then pull the entire auger/gearcase out as an assembly. Once out it is simple to work on it. (If the augers are free and remove easily)

If you failed that main gearbox, that can be slid right off the back and disassembled.

Either case, be certain to reinstall that center support bracket and tighten it. I had one come loose, not a pleasant word was uttered!

 

[dtanner]

Art :

fill us in ? what makes you think the gears are stripped ? I hope you did not strip the spline in the second stage fan like I did .The second stage fan is pinned fast to the the shaft on the out side gear box.You have to take the bolts out and pull the side off to get to that gear.I can post pictures if needed. later Don T

 

[aaytay]

Sorry guys, I should have been more clear... It's the primary gearbox that's bad.

The reason I know it's bad is because (with the tractor turned off) I can kneel down next to the blower, hold the 2nd stage fan with one hand, and spin the pulley on the back of this gearbox the opposite direction with the other hand. You should be able to spin one side and not be able to stop the other side.

 

[dtanner]

Art

If you hold the second stage impeller from moving and can still spin the pulley on the gear box means that the spline inside the second stage impeller could still be striped. Do the same thing again and watch to see if the shaft going into the second stage impeller is rotating. If it is you stripped the second stage impeller spline like I did.

 

[jdiederichs]

Art,

What Don said!

I think he is correct, having btdt himself.

Don, thanks for 'splaining that problem. Any advice on repairs?

 

[dtanner]

Jim D

I have a plan ; here is a picture of a splined shaft used on a oil delivery truck from the PTO to the pump that pumps oil . his would be used on trucks that would deliver oil to your house. i was told this spline would stand a lot of torque.

I might add that they fit perfectly.

as you can see one fits inside the other and can move (slip).

The outside of the spline will be welded to the gear box spline and the smaller ID spline will slip inside the second stage blower fan and be welded to it.This will let the gear box slide and move around but won`t allow it to strip again.The second stage blower spline on my 450 is stripped and the gear box spline is damaged. So I would have to spend much $$ to buy a new shaft and the second stage blower fan to do a proper repair . To many dollars for me.

 

[dtanner]

Guys I do need to get the 450 blowing snow again.It did work great lol. With the diesel I could have a cab heater and blow snow in a T shirt . just wish I had a Cab like Art got .

https://www.youtube.com/watch?v=D9MCvBtBY3k

 

[aaytay]

Jim/Don-
I can only HOPE that it is the spline. I'll do that check Don mentioned when I get a chance. Maybe this weekend...

I'd rather have the spline go bad rather than the gears, because there's a possiblity I can refit something on to repair the splines. I can't fix busted up gears. (I don't have a machine-shop in my garage.)

I wonder why that shaft is splined? It's as if it has to move (slide) as it's working. Too bad you can't just weld it up and call it GOOD.

 

[dtanner]

Home of the Plow Special

Art , I think the spline is out of the rear gear box because of the belt on the pulley. with the 450 lifting up the load on the belts and pulley change.So as to allow some movement they added a spline instead of a fixed connection. Also so you can disassemble the unit

. If you want to pay shipping I`ll send you a few " of the spline I have here. I bought 2' for 10$ .I bet it would make a great Cub drive shaft also.

 

[jdiederichs]

I agree with Don, the spline is for ease of assembly, as well as suitability with other MTD products. That basic blower was used in all kinds of applications by them.

I sure hope the gears are good! If the gearbox is not working right, there always is the chance of shearing a woodruff key (fingers crossed)

When you have it all apart, make very sure that the impeller paddles are all straight, or straighten them if bent back. That alone makes a huge difference in capacity and performance.

 

[dtanner]

ART

( there always is the chance of shearing a woodruff key (fingers crossed) )

I AGREE JIM AND WE HOPE HE IS THAT LUCKY. I did find a grade 8 bolt where I did not want it $$$.

You got me thinking and WE need you to tell us what you found .

 

[dtanner]

Art

Come on and tell us what you found. You must have checked out the gear box by now ?

 

[jbaker]

Don now your going to have to clean the light at the top of the pole off.. nice

 

[aaytay]

Don-
I was literally in the garage when you posted that "tell us what you found" message. LOL

Well, it looks like you guys were correct. After pulling the gearbox off, it appears as though the splines on the impeller shaft are stripped out. The splines on the gearbox itself look good, but it doesn't look like there was much "interlock" of the splines because there is old grease in the splines on the gearbox end of the coupler. Which end failed on your blower, the gearbox (male) end or the impeller shaft (female) end?

I didn't have time to pull the rest of the blower apart to confirm that it's the impeller shaft, but from what I'm seeing, it looks pretty conslusive that this is what I'm dealing with. Thanks for your help so far, I'll post up what things look like once I get a chance to remove the impeller.

 

[dtanner]

Art ; I think the problem is water getting in the impeller and rusting up the spline. the gear box spline is hardened so it would not be affected as fast. I want to take the spline I have here and see if my welder friend can center it a weld it fast.The only issue I see would be vibration . I see charlie has your part Model 450 Blower Fan Assembly PN/ 784-5145 USE 784-5145-0637 $150.00 . for me shipping would be to much to go with new. If you do replace the second stage blower I would put lots of grease in it that is not affected by water to hold back the rust.I think this is a poor design and will be a problem with all the 450 and 451 snow blowers.I showed my spline that I posted to my welder and he said we would be farther ahead to use square tubing to cover the spline and weld in another piece so it could all slide apart to service it. The square tubing on the gear box could be pinned or welded . But I will have this running again next winter. It moves so much snow that I need to have it working. Let me know what you decide to do, I`am interested in if you will by new or mod the problem better than original.

 

[jdiederichs]

I am not sure if the gearbox spline is an SAE standard spline or not. If it would be, Kohler engines have a spline insert kit for engines designed to power hydraulic pumps, when using the pump mounting flange. No, not like a log splitter, I mean a true high displacement hydraulic pump.

They offer the spline insert kits to repair crankshafts whose splines have worn out. These are available in 9,11 and 13 spline kits.

Not sayin' thay would be right for the gearbox spline, but if they are???? it would be a simple repair of the impeller. Let me see if I can find the service bulletin #.....

 

[aaytay]

Thanks for the thoughts guys. I'll keep you posted on what I find once I pull it apart further.

 

[jdiederichs]

Art and Don,

I sent you a pm with the spline info, but should have also posted it here. If you would be so kind...

 

[kmcconaughey]

This just in! Thanks Jim!