Another MX6 Brush Hog Failure

[GreatWhitehunter]

I think the worst part about this whole saga, is the MX's are highly reguarded line and it seems the 6 is the one unit with the issues. I like the design and gauge of the units. One would think that deere would step up to the plate on fixing this as I'm sure there's a hefty margin on these cutters.

Matt

 

[brown40]

It also has happened to the MX5 and MX7 models--anything with the "dual deck" and extra long output shaft. Spanish, Mexican or Chinese, Comer made them for Deere, and Deere printed the new country of origin and offered longer warranties to increase confidence in the same old gearbox. A global economy.

 

[Sawyer Rob]

It also has happened to the MX5 and MX7 models--anything with the "dual deck" and extra long output shaft. Spanish, Mexican or Chinese, Comer made them for Deere, and Deere printed the new country of origin and offered longer warranties to increase confidence in the same old gearbox. A global economy.

What does the "dual deck" mean?

Does the MX6 have a longer output shaft?

SR

 

[Turbys_1700]

The MX6 has 2 top decks that hide the support brackets for the mower. I guess the argument is that water runs off better. It is a really clean looking deck. Makes it heavier. Better? You decide. I run a Brown.

 

[GreatWhitehunter]

It also has happened to the MX5 and MX7 models--anything with the "dual deck" and extra long output shaft. Spanish, Mexican or Chinese, Comer made them for Deere, and Deere printed the new country of origin and offered longer warranties to increase confidence in the same old gearbox. A global economy.

Can you point to where you heard this? I had only heard of a few MX5's and now on the 7's?

Matt

 

[brown40]

Well, I have a MX5 that sheared the output shaft, and in the search for a replacement found the gearbox used on the 5, 6, and 7 series were all the same--also the same were formerly used by a company called Tiger out of Canada on their batwing mowers.
I suspect there are a lot more 6's out there than the other two (single spindle 7's don't seem too popular for any shredder line). I have to admit I have not seen a published failure regarding MX7 or Tiger mowers gearboxes, but given that the output length and gearbox design are the same, I would consider them to be at risk for the same episode. I replaced my busted spanish JD (Comer) with the updated Chinese gearbox (also from Comer) that uses a castle nut instead of a bolt for attachment.
The output shaft is definitely more robust now, but to reuse an MX deck you need an output that is 50-100% longer than a typical output shaft is... I could not find anyone but Comer making one that spans the distance.
The MX's use two sheets of steel to keep the topside free of dents (except the front 25% or so) and do all the damage on the underside, and ties the two together using a steel bowl. The spacing from the top of the top deck to the bottom of the steel reinforcing bowl (that spans and ties together the decks and mounts the box) are why they are so hard to find a replacement for. I don't think batwings and larger mowers tend to have quite as varied a diet as the smaller shredders get.

 

[MF283]

Is it just the deck design, i see other brands with the smooth deck design & wonder if they're using twin decks as well?
Also assuming all manufacturers are using basically the same gear boxes?

Ronnie

 

[Turbys_1700]

Some smaller manufacturers don't use the smooth top designs. Deere design is unique in that it is a two piece smooth top design. Bush Hog. Woods, etc...use a single piece on top. It helps facilitate water run off.

 

[JWR]

I suspect there are a lot more 6's out there than the other two (single spindle 7's don't seem too popular for any shredder line). I have to admit I have not seen a published failure regarding MX7 or Tiger mowers gearboxes, but given that the output length and gearbox design are the same, I would consider them to be at risk for the same episode. I replaced my busted spanish JD (Comer) with the updated Chinese gearbox (also from Comer) that uses a castle nut instead of a bolt for attachment.

For whatever it is worth, I had a Deere MX6 with the Spanish-made gearbox for 10 years driven by a JD4700. I hit some hellacious rocks with it,usually mowed pasture weeds and some bushes and saplings. Clusters of 5 or 6 2" thick autumn olive bushes definitely slowed it down but no failures. Hardest steel blades I ever saw. I did have the stump jumper fly off a couple of times after 4 or 5 years ownership but that amounted to me failing to realize the torque specs. Once it was back on there with a socket buster of a long cheater arm it was just fine. I read all these MX6 horror stories but I was either lucky or mine was a good one. Meanwhile, in later years I use a Bush Hog 297 seven ft hog and it is 1460 lbs and a lot stronger than the "medium duty" tag implies. Driven by a MF2660. Bush Hog parts books show a different part # for each of the 5,6 and 7ft unit gearboxes. Mine developed a crack and began to leak lubricant near the hold down bolt pattern, vertical, after 4 years use. Dealer said I had abused it. I said he was full of bullcrap. Bush Hog Corp.said they had a few do that, neither they nor their supplier could explain it AND THEY WOULD BACK IT REGARDLESS OF THE GUARANTEE. The harsh dealer put the new one from Bush Hog on. He failed to get the nut tight enough on the stump jumper but other wise I'm good to go. I don't see anyone backing their cutters like Bush Hog. It is a shame to hear the response Deere has been reported to be giving their customers in these forums.

 

[brown40]

Some of the other manufacturers use different gearbox ratios through their line--I figured they were targeting a particular blade tip speed at PTO speed. As I type, if memory serves, the MX6 blade tip speed was as high as any I found (I wanted that over the MX5 after I bought--the extra 6" of radius on each side pushed the 6 up over 12000 fps). Either way I broke the smaller one instead, and the cut quality was fine before and after. Just broke and got disavowed.
What Bush Hog did for you, was what I had kind of expected from JD, and what I will purchase for going forward.

 

[Sawyer Rob]

Also assuming all manufacturers are using basically the same gear boxes?
Ronnie

I'm not sure i understand what that means??

But, I'd have to say, NO they don't all have the SAME basic gear box...

SR

 

[MF283]

Origin of manufacture is what i meant. Seems to be the longer length is the culprit here regardless of where they were made.

Ronnie

 

[deere5105]

Thought I had a “good one” until this afternoon. Mowed most of the morning. No issues. Mowing around plowed field. Hit a small dirt pile and heard change in sound. Looked back and stump jumper sitting in the mowed grass. Over the years have had MUCH worse encounters, but today was it. Sheared output shaft. Had contemplated selling it couple years ago, but thought I was good. I typically skip the clutch every spring, but admit I had not yet done it this year.

 

[JimR]

I'm not sure i understand what that means??

But, I'd have to say, NO they don't all have the SAME basic gear box...

SR

They absolutely do not all have the same gearboxes. John Deere likes to be different so that you have to use their parts at a premium price.

 

[JimR]

Thought I had a “good one” until this afternoon. Mowed most of the morning. No issues. Mowing around plowed field. Hit a small dirt pile and heard change in sound. Looked back and stump jumper sitting in the mowed grass. Over the years have had MUCH worse encounters, but today was it. Sheared output shaft. Had contemplated selling it couple years ago, but thought I was good. I typically skip the clutch every spring, but admit I had not yet done it this year.

Go on EBay and search for the shaft for your mower. There are companies making these shafts now due to the high demand for them.

 

[JimR]

Origin of manufacture is what i meant. Seems to be the longer length is the culprit here regardless of where they were made.

Ronnie

It is the length and size of the gearbox shaft that is the problem. The "made in Spain" shafts are the ones that are breaking the most. The China shafts are much more beefier. I have seen and heard of both of these gearboxes shearing shafts. I would really like to see John Deere go out with one of there mowers and try to cut the size diameter trees that they claim these mowers are capable of cutting. I think they would be in for a rude awakening. I have sheared gearbox shafts on both the made in Spain and made in China gearboxes. Neither of those breaks was from hitting rocks or stumps or cutting down larger diameter trees than these mowers should be able to handle according to John Deere.

 

[Ken]

The length of shaft possible cause but the 2 that I have seen is where a groove is cut into the shaft to hold a lock ring. look closely at your broken shaft and see where a oval smooth cut deeply into the shaft.
anyone know the part number of where to locate a replacement shaft.
ken

 

[deere5105]

Go on EBay and search for the shaft for your mower. There are companies making these shafts now due to the high demand for them.

Will check that out. Have been pleased with the quality of cut and the unit is in good shape. Would like to get it back going. Thanks for info.

 

[JimR]

Will check that out. Have been pleased with the quality of cut and the unit is in good shape. Would like to get it back going. Thanks for info.

These shafts do break at the clip ring slot because the shaft is thinner there. Makes ure you buy the right one. The Spanish version is not the same as the Chinese version. Take your gearbox apart to see the shaft before ordering one.

 

[deere5105]

These shafts do break at the clip ring slot because the shaft is thinner there. Makes ure you buy the right one. The Spanish version is not the same as the Chinese version. Take your gearbox apart to see the shaft before ordering one.

Thanks for heads up. I looked up the part on JD Parts and see there appears to be two different versions of the Bevel Gear. I believe mine is the Spanish version. If I can replace the broken part and get another 14 years out of it I will be better off repairing.