OH POO! What did I do?

[7snakes]

Have a jd mx6 rotary cutter. I have been using for about 3 years with little problems. Yesterday was clearing some brush at the edge of a creek bank. Backed up to the edge of the bank,lowered the cutter and hit a fair sized hidden stump. Realized what was happening and raised the cutter to discover it wasnt cutting anymore. Pto shaft was still rotating. Turned off the mower and inspected underneath to find the jumper pan and blades were missing which I found in the creek. Not knowing anything about how these shafts/gearboxes work, it is clear that a shaft of some sort broke. I then noticed oil pouring from the now gaping hole where the shaft connected. Should the slip clutch have prevented this from happening? How big of expense am I looking at to get this fixed? What part is broken? I have hit things before but have never had this happen.

 

[Willl]

Should the slip clutch have prevented this from happening?(

Sure should have, provided it was adjusted correctly and not rusted together.

Did you do a 'preseason' clutch adjustment ?

 

[rasimmo]

Yes the slip clutch should have prevented it. That is what it is there for. You broke the output shaft from the gearbox. It should not be too expensive to repair (a lot cheaper than a new cutter anyway). You should just have to buy the shaft and the seal. I would do something about that slipclutch too.

 

[RoyJackson]

Wow! That thing is really sheared off!!

Right off the bat, you're going to need a new shaft. Personally, I don't think I'd trust a weld repair of any sort...not when you consider the abuse these cutters must endure.
As far as replaciing that shaft (and hoping you can salvage the jumper pan and blades), you'll need to get a service manual.
If you can't do the job due to lack of skills and tools, I suggest you get an estimate from your dealer before any work.

Good luck!

 

[RoyJackson]

perhaps you didn't have a proper shier bolt in place, as for the repair you might find a used gearbox/shaft , did you locate the blades and disc? if so they are probably reusable,

He has a slip clutch and did find the jumper pan and blades.

The slip clutch was probably frozen (with rust) or not adjusted correctly.

 

[Ford tractor]

Have a jd mx6 rotary cutter.

Should the slip clutch have prevented this from happening?

What part is broken?


How big of expense am I looking at to get this fixed?

I have hit things before but have never had this happen.

The Mx 6 is a good cutter -- when it works. However, there have been many reports of that exact failure. It seems to be a common flaw on gear boxes from (I think) Spain. (more below)

The slip clutch is the worst option for what I'll label "casual users". You MUST test and adjust a slip clutch every time a machine sits for more than 2-3 weeks. MUST. If you don't, the clutch will rust together and become a "No slip clutch". When that happens, expensive things occur. I'm going to guess that you probably didn't realize that (it's in the manual, but who obsessively reads it?). OK enough chastising --> you've learned a lesson and are now teaching others.


The part is the gear box output shaft. It's NOT SUPPORTED by JD.


Are you handy with tools? If so, you can take it apart and bring the pieces to a VERY HIGH QUALITY WELDING SHOP. VERY HIGH. The shaft is hardened, so they will have to heat treat it before and after. Weld repair is probably going to be in the 4-500 range. IF you can get anyone to do it. Most shops won't touch a rotary cutter output shaft. Too much liability. The pan can fly out.

The JD solution is to sell you a new style gear box that won't fit the current pan / cross bar. About $750 for the gear box and about the same for the pan. Plus shipping of those not so small or light items. (ouch); You may want to check that it is indeed out of warranty. I think the gear box is 5 years (could be 3).


I hate to say it, but your best solution is probably to park the cutter in the woods and buy a new unit from Brush hog or Woods. I have a Woods Brushbull 600 and have 10 years of service on it. The Brushbull 720 would be the replacement size to the MX6. The Brush hog brand is reported to be slightly better. The 290 or 320 series (I forget which) is probably what you would want.

 

[7snakes]

Uh uh well no preseason check of slipclutch was done-some have to learn the costly way Where or how can I learn how to do this in the future? By the way, should the blades quit turning relatively quickly when turning off the mower? They always continued for at least a minute turning even when it was brand new. My yard tractor blades stop almost immediately.

 

[Ford tractor]

I think you're screwed on the warranty. The recently extended it to 5 years, so you are most likely out of luck with it being 3 years+ old.

 

[RoyJackson]

Uh uh well no preseason check of slipclutch was done-some have to learn the costly way Where or how can I learn how to do this in the future? By the way, should the blades quit turning relatively quickly when turning off the mower? They always continued for at least a minute turning even when it was brand new. My yard tractor blades stop almost immediately.

Just do an internet search for "Adjusting Slip Clutch"...but the procedure may be in your Operator's Manual (first place to look).

As far as the spin down time...yeah, cutters can take a minute or more...so, yours is typical.
If you reduce the tractor's engine RPM first, that will be easier on your PTO.

 

[blueriver]

Why can't the OP tear the gear box down, order the new shaft and put it back together?

 

[blueriver]

Why can't the OP tear the gear box down, order the new shaft and put it back together?

John Deere - Parts Catalog

 

[RoyJackson]

Why can't the OP tear the gear box down, order the new shaft and put it back together?

Depends on his skills and if he has the tools.

 

[Willl]

Snakes, can you find a serial number on it?

 

[blueriver]

Depends on his skills and if he has the tools.

Correct ... I thought I read someone advised him to park it in the woods and get a new one. Even with a lack of skills he could at least get the parts and have a shop do the rebuild.

 

[rasimmo]

Correct ... I thought I read someone advised him to park it in the woods and get a new one. Even with a lack of skills he could at least get the parts and have a shop do the rebuild.

In the post that said that, it also said the parts were not supported by JD. I am not sure though.

 

[RoyJackson]

Correct ... I thought I read someone advised him to park it in the woods and get a new one. Even with a lack of skills he could at least get the parts and have a shop do the rebuild.

That may be the best way to go if the OP has to have all the work done...and, the condition of the cutter may not justify putting much money into it.
But, with al the good advice he's got so far, at least he can make an informed decision.

 

[blueriver]

In the post that said that, it also said the parts were not supported by JD. I am not sure though.

Okay ... when I looked them up on the John Deere Parts Catalog they where there ... of course that don't mean they have them!!!

 

[blueriver]

That may be the best way to go if the OP has to have all the work done...and, the condition of the cutter may not justify putting much money into it.
But, with al the good advice he's got so far, at least he can make an informed decision.

Roy thats also true. I don't know what a shop would charge.

 

[clemsonfor]

Yes the blades will turn for a minute or so after you turn the cutter off, has nothing to do with the clutch.

If you can get the shaft i think you could get it done for half the cost of a new one?

Here is a question, how handy are you? CAn you cut and weld metal, take things apart?

Also does anyone know if the cheaper gearboxes from Ag supply will fit? You can get a 40HP gear box for $120 in store or shipped(obviously plus shipping). This would be the cheapest solution. The picture of them on the catalouge looks just like the one on my Jbar BH. They are shear pin boxes. If they wont fit and you can weld or have some one who can you can make it fit!

 

[MHarryE]

The shaft didn't break from this one incident. The lines you see on the fracture surface are called beach marks. They are created as the shaft fatigued. The rough area in the center is the final fracture. There is a step on the shaft OD where the shaft was machined - probably the snap ring groove. If you look at the JD Parts Catalog, it shows 3 possible gear boxes. The ones shown as item 28 and 30 illustrate a shaft with a snap ring groove. Item 32 is the later design (shown by the serial number range having no end number) and the snap ring grove has been removed. The illustration shows that instead there is a shoulder in the middle of the shaft where the snap ring was previously located. It is very likely that they found the original design was subject to bending fatigue failures. That snap ring groove not only weakens the shaft by the reduction in diameter, but the corner of the groove creates a stress riser that magnifies the fatigue factor. The new design is much more expensive because it is made by machining the shaft out of a larger diameter bar, but my rough estimate is its at least twice as strong as the original design in the loading that a rotary cutter sees. It looks like you can get a replacement for the failed part if the parts catalog is correct - it doesn't say anything about not being serviced separately - that you have to buy the entire box, blade holder, and blades, but it looks like something on which you would expect a repeat failure. A shear bolt or lower slip clutch setting isn't going to stop a fatigue failure like this - it is going to happen sometime although a lower slip clutch setting will prolong life.