# Tractor transmission gear repair options



## Novaman_68 (May 30, 2017)

I've got a small 16hp Kubota diesel tractor that has some damaged transmission gears and I'm exploring repair options. The gears drive the PTO and power the front axle (4wd). These gears are unavailable new and the gears I bought from salvage are completely wrong. 
Option 1: Make completely new gears. This is the least desirable because they are internally splined and I would think they would need to be heat treated. 
Option 2: Build up the damaged gear teeth with silicon bronze and recut the teeth. 
Option 3: Obtain gears with the same pitch, tooth count, pressure angle, etc. and machine the center out of the new gear to press over the splined stub (after I machine the damaged teeth off)
Option 4: Keep hunting for used gears and hope I can find the right parts.
 I've attached a pic of two of the three damaged gears.
Any advice would be appreciated


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## 682bear (May 30, 2017)

In my opinion, option 4 would be best, but if you can't find the gears, option 2 would be a close second...

Are the splines on the shaft ok, or are they damaged also?


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## Novaman_68 (May 30, 2017)

The splines are fine on all 3 gears. I'm leaning towards option 2, but I'm not sure if the bronze will be strong enough.


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## Uglydog (May 30, 2017)

Do you have any farm implement stores.
Especially the old style where they don't keep computer records of what they have.
We have a few around here, there is always an elderly gentleman in the corner drinking coffee who somehow remembers that there is a box upstairs under the window with some old parts.
I'd also check what is called FleetFarm which is a large box store which does some farm stuff and carries some gears.

Daryl
MN


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## Alittlerusty (May 30, 2017)

What's the part numbers for the gears ? Model# and serial number of the tractor? And have you tried posting on tractorbynet? The members there are as good at tractor help as the members here are at machining help


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## Novaman_68 (May 30, 2017)

No luck for the old farm store around here. 
I haven't tried posting at tractorbynet yet, but I might give that a try. I have 3 different part numbers for each gear. I don't have any of the part numbers with me at the moment, I will find them when I get home after while.


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## DaveInMi (May 30, 2017)

I don't know what the gear is made of but a good welding supply store might have other options for weld build up material.  I used machineable nichol rod for a project a few years ago.


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## Uglydog (May 30, 2017)

If you want to get me all the specs including DP I'll check around here.
They'd really like to get rid of some of this old inventory.

Daryl
MN


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## RJSakowski (May 30, 2017)

In terms of options, I would go #4, #3, #1.  I would be concerned with option #2 as the gears are obviously used in a high load situation and it would be difficult to make a repair as strong as the original part.  Pieces of metal swirling around in your gear box could do even more damage.

Finding the gears could prove to be difficult.  They are highly customized parts which would not be likely to be stocked by anyone other than a Kubota dealer.  You may have better luck looking for a scrapped tractor using the same parts.  I have found several sites online in my quest for parts for my Ford 8N that sell new and used parts.

You might check on ebay and c/l for parts to fit your tractor.  Even if the parts aren't what you need, the person selling may be parting out a tractor and still have the parts you need sitting on their shop floor.

If you can find a "where used" list for the parts you need, you may find that they fit several models which will allow you to expand your search.

Good luck!


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## woodchucker (May 30, 2017)

I like #3, it seems like the easiest to accomplish.
But b4 you do, make sure the gears mesh fine b4 damaging the old. Once you know for sure, you at least have a gear master if you have to make it completely.
I'm imagining that it's hardened too, so I would get a carbide drill bit, and pin the 2 together b4 any welding of the 2 pieces. Just a little more insurance.


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## Silverbullet (May 30, 2017)

Another thought find a used one that may have blown motor and buy it for parts . May not be as costly making new ones.


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## RandyWilson (May 30, 2017)

I assume the 3rd unpictured gear is in just as a bad shape, and the reason it was disassembled is because it was jumping out of engagement. The damage is consistent with shifting non-syncronized gears while in motion. If that is the case, engaging the PTO while in motion, then the odds of finding good used gears are as low as finding good cluster shaft for an MG 3syncro box. Option 2 may well work *if* a technique can be devised to only engage when both shafts are stopped. 

  I would look hard for option 3. Both industrial gear suppliers and automotive racing transmission manufacturers.


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## DAT510 (May 30, 2017)

I know there are Industral Equipment/Heavy Equipment services that repair gears.  You might call all a place like this just to see what I would cost.  http://www.ersgearbox.com/gearsrepair/


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## benmychree (May 30, 2017)

Uglydog said:


> If you want to get me all the specs including DP I'll check around here.
> They'd really like to get rid of some of this old inventory.
> 
> Daryl
> MN


These gears would not be DP, they would be metric module or a permutation of that system.


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## Uglydog (May 30, 2017)

Yep.
That makes sense: Kubota.
Unlikely they will have these laying around.

Daryl
MN


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## Terrywerm (May 30, 2017)

Try getting in contact with one of the LARGE tractor salvage yards. They employ a parts search system much like many of the automotive salvage yards. You submit a query at one yard, and if they don't have it, they put the query out to all of the member yards to see if someone has it. Many of the tractor salvage yards work together as well, even when they are competitors, as it results in a net gain in sales for all of them.

I get into some of the large tractor salvage yards in the upper Midwest on a semi-regular basis to haul out their scrap tires. I don't see many Kubotas in the yards yet, but there are a few, with more appearing every year. There may be more available in areas where the smaller tractors have been popular for a longer period of time. I am not affiliated with any of them, but you might try contacting one of these:

Worthington Ag Parts.  www.worthingtonagparts.com  They have locations in Worthington MN; Audubon IA; Evansville WI; Goldsboro NC; Leesburg IN; Watertown SD; St. John's MI; Sikeston MO.
All States Ag Parts   www.tractorpartsasap.com    Locations in Downing WI, Black Creek WI, Salem SD, Ft. Atkinson IA, Bridgeport NE, Hendricks MN, Sikeston MO, De Soto IA, Lake MIlls IA.

There are others, but these are a couple of the big players in my area. They both offer online search and ordering for parts as well. Contacting the small yards may get you results, but it would be a slow, time consuming process.


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## Scruffy (May 30, 2017)

I'm with randy Wilson. Theirs a reason tractors go to the bone yard. There's a weak or wear point in everything.as far as finding one with a blown engine, I'd have to say Google luck.  Kurosawa and yanmar so are all but indestructible  I've got 2 .
Thanks ron


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## AGCB97 (May 31, 2017)

Free and easiest way to start is "get your GOOGLE going". Spend time and try different search topics. if_ more than one of these things were made, chances are great someone else had the same problem AND wrote about it. Follow leads even if they don't at 1st look like they're going your way. Hours spent with clean hands on computer may save you weeks with dirty busted knuckles_


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## cathead (May 31, 2017)

What's up with Kubota?  Don't they support their own stuff?  I would get after Customer Service/Support.

Maybe raise a little Cain(not the cane that grows in Brazil).............................................


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## rock_breaker (May 31, 2017)

Getting here quite late but RandyWilson  explained why they fail (my 3510 Branson has the same arrangement) and Terrywerm in my book has an excellent approach. Searching the salvage yards makes sense. Not trying to belittle skills here but IMHO welding or brazing gears can lead to problems down the road that are temporary repairs to get back into production while you find factory replacements..
Have a good day
Ray


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## samthedog (Jun 1, 2017)

I have experience with option #2. We had a David Brown tractor with damaged gears and built up the gears by brazing. We used a flex-shaft grinder to grind them to shape and blued a master to make sure we matched the gear teeth as accurately as possible. We had the tractor in service for 19 years until we lost it in a bush fire. The gearbox held up under heavy use and the solution worked perfectly.

Paul.


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## Novaman_68 (Jun 1, 2017)

Thanks for all the replies. This tractor was abused before I got it. Looking at the way the gears were damaged, I think someone was running an attachment off the PTO shaft without a safety clutch and probably hit something hard which caused the gears to give. It just so happens that the PTO and 4wd drive share common transmission shafts. This is not a common problem from what I've seen.  Luckily I've managed to find replacement parts in a salvage.


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## jdedmon91 (Sep 28, 2018)

Novaman_68 said:


> I've got a small 16hp Kubota diesel tractor that has some damaged transmission gears and I'm exploring repair options. The gears drive the PTO and power the front axle (4wd). These gears are unavailable new and the gears I bought from salvage are completely wrong.
> Option 1: Make completely new gears. This is the least desirable because they are internally splined and I would think they would need to be heat treated.
> Option 2: Build up the damaged gear teeth with silicon bronze and recut the teeth.
> Option 3: Obtain gears with the same pitch, tooth count, pressure angle, etc. and machine the center out of the new gear to press over the splined stub (after I machine the damaged teeth off)
> ...



Finding used gears is the only inexpensive option. The original gears was made out of alloy steel heat treated and probably was made with a specific gear form that more than likely shaved. So trying to use any other gears will not work. 


Sent from my iPhone using Tapatalk


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