Backhoe Cracked Transmission case between bolts attaching backhoe

[SGreene]

I bought a new Kioti NX4510 last fall. In April of this year I began to experience a hydraulic leak in the rear of the tractor. In July, after the leak had become much worse, the leak was traced to a crack in the transmission case between two bolts that attach the backhoe mount to the tractor. This fall, Sept. 7, I experienced another major hydraulic leak coming from the back of the tractor. This time it was traced to a crack between two bolts holding the backhoe mount on the other side of the transmission case. Is anyone else experiencing a similar problem? Solution?

Alas, the local dealer cannot even order parts for a "high cost" warranty claim until he has factory approval via a "HIgh Cost Repair Code" (HCRC). Kioti's Customer Service Administrator (CSA) has told me that is Kioti's policy and that it is not subject to review or discussion. The CSA said that if anyone proceeded with work without an HCRC, they would be responsible for the full cost of the work regardless of any warranty claim. My dealer, bless his heart, has taken it upon himself to order the part because Kioti has yet (today is November 1) to approve an HCRC. Has anyone else bumped into this sort of red tape and delay from Kioti?

Last, should it be possible to damage the transmission case via operation of the backhoe? Is it a common practice to mount backhoes to a tractor's transmission case rather than to the tractor's frame? Am I wrong in thinking that as long as no damage is done to the backhoe itself, there should be no damage to the tractor to which it is mounted? Or, expressed differently, how could backhoe operations, operations done within the operating constraints of the backhoe itself, cause damage to the tractor to which it is mounted?

Thank you all for your thoughts.

Good morning: I just came across your post. I started a thread and wrote a complete write up of this exact issue here on TBN but the search function doesn't seem to go back far enough to find it. I'll explain my experience which is in line with yours.

I purchased a new 2018 NX6010 rops with 2485 backhoe Feb 2018 and took possession of it June 2018 with 4hrs on the odometer. I immediately put the tractor to work digging with the backhoe and 12" wide bucket, utility and water lines for my new home build. I checked and re-torqued all lug nuts, backhoe, and FEL hardware at 20hrs. At 40hrs I experienced catastrophic failure with the backhoe. The bolts for the BH mounting brackets pulled out of the rear end center section and transmission and the BH broke free from the machine. The transmission/rear end center section castings of the tractor failed and shattered to pieces around and between the four bosses.

My findings: Upon inspection of the threads in both the bosses and on the bolts, I found the hardware for the BH brackets to be too short. Bolts and bosses showed only 3 - 4 threads were actually engaged as the casting material pulled and stayed on the bolts. I used a micrometer to measure the depth of the bosses and I compared that to both the thickness of the clamping load as well as the length of the bolts. My finding was that all hardware associated with BH mounting brackets were only engaging about 1/4 of the thread depth of the bosses.

Kioti's findings: I brought my findings to my dealer and I worked with their techs. We found multiple issues. First, we fount that the hardware being used for the BH mounting brackets were indeed too short. Second: the rear mounting bracket on the rear differential center section is a 90 degree bracket that bolts to both, the 4 bolts underneath the center section, as well to the 4 bolts for the PTO guard. This bracket is supposed to be welded as a 90 degree plate so that it can bolt to both the under side bolts and the PTO bolts on the back. We found this bracket was obtuse to 90 degrees not allowing it to bolt flush to the two mounting planes, and the weld was placed on the inside corner pushing the bracket away from the mounting surface. This created more gap for the already too short hardware to tighten the bracket to the rear end housing.

Failure event: The 4 bolts around the PTO cover pulled out first. These simply stripped out the few threads that they were engaged with. This put all load stress on the bottom 4 M12 bolts for the bracket. By losing that plane of support, the flexing cracked the housing casting between the M12 bolt holes until the casting around the bosses completely failed and gave way destroying the rear end housing.

Warranty: Kioti warrantied all materials and labor. It took 3 1/2 months to fix. The tractor's back half was completely disassembled and the trans/rear end housing replaced. The dealer got $6,000 for doing the warranty work but they said it would have cost me about $8,000 if warranty would not have covered the damage. Kioti also stated they were performing a company wide recall of the hardware kit and replacing it with longer hardware. Another note; Thread locker is not used from the factory, nor was it used upon final assembly at the dealer. It was explained to me that the use of thread lockers is up to individual technicians and is not mandated.

Finally: I think it is important to add a CYA note here. I had checked and re-torqued all fasteners associated with BH the day before the failure at 20hrs. I put 35hrs on the machine in 3 days. My dealer tech was at my house 1 hr earlier on the day of failure for an emissions issue with the tractor. He seen what I was digging with the BH using the 12" bucket, and how I was doing it. He stated that is what the unit is built for. This cleared me of any "user abuse" accusations. I also took plenty of pictures of the tractor failure while it was still in position of use, as well as the ditch depth and material being dug when the failure occurred.

To the OP: I hope this info gives you some ideas as to what and why the failure occurred. I used to have a bunch of pictures and diagrams of the parts and situation but i don't anymore. Good luck sir.

Steve

 

[blue1jassid]

Hi Steve,
Thank you ever so much for your detailed explanation of the issues you faced with your backhoe. I am new to the forum and don't really know how to conduct a search on this one or any other for that matter. Suggestions on how to do a better search to try to determine if NX model Kiotis are experiencing more backhoe mounting issues than we might be aware of?

My tractor is still with the dealer and no updates from Kioti or the dealer on whether a high cost repair code (HCRC) has been issued. A week and a half ago the dealer said he expected the parts soon but I haven't heard anything more nor anything about whether the parts were obtained "independently" or after a HCRC had been issued.

Best to you Steve and all.

Blue Jassid

 

[SGreene]

Blue, I found that thread I was referring to about my BH bracket issues. Post #16 has diagram of the affected parts we are talking about and my description of failure. Hope it clarifies a few things.

https://www.tractorbynet.com/forums/kioti-buying-pricing/401288-soon-new-owner-2.html?highlight=#post5190308

Good luck sir.

 

[JimR]

Good morning: I just came across your post. I started a thread and wrote a complete write up of this exact issue here on TBN but the search function doesn't seem to go back far enough to find it. I'll explain my experience which is in line with yours.

I purchased a new 2018 NX6010 rops with 2485 backhoe Feb 2018 and took possession of it June 2018 with 4hrs on the odometer. I immediately put the tractor to work digging with the backhoe and 12" wide bucket, utility and water lines for my new home build. I checked and re-torqued all lug nuts, backhoe, and FEL hardware at 20hrs. At 40hrs I experienced catastrophic failure with the backhoe. The bolts for the BH mounting brackets pulled out of the rear end center section and transmission and the BH broke free from the machine. The transmission/rear end center section castings of the tractor failed and shattered to pieces around and between the four bosses.

My findings: Upon inspection of the threads in both the bosses and on the bolts, I found the hardware for the BH brackets to be too short. Bolts and bosses showed only 3 - 4 threads were actually engaged as the casting material pulled and stayed on the bolts. I used a micrometer to measure the depth of the bosses and I compared that to both the thickness of the clamping load as well as the length of the bolts. My finding was that all hardware associated with BH mounting brackets were only engaging about 1/4 of the thread depth of the bosses.

Kioti's findings: I brought my findings to my dealer and I worked with their techs. We found multiple issues. First, we fount that the hardware being used for the BH mounting brackets were indeed too short. Second: the rear mounting bracket on the rear differential center section is a 90 degree bracket that bolts to both, the 4 bolts underneath the center section, as well to the 4 bolts for the PTO guard. This bracket is supposed to be welded as a 90 degree plate so that it can bolt to both the under side bolts and the PTO bolts on the back. We found this bracket was obtuse to 90 degrees not allowing it to bolt flush to the two mounting planes, and the weld was placed on the inside corner pushing the bracket away from the mounting surface. This created more gap for the already too short hardware to tighten the bracket to the rear end housing.

Failure event: The 4 bolts around the PTO cover pulled out first. These simply stripped out the few threads that they were engaged with. This put all load stress on the bottom 4 M12 bolts for the bracket. By losing that plane of support, the flexing cracked the housing casting between the M12 bolt holes until the casting around the bosses completely failed and gave way destroying the rear end housing.

Warranty: Kioti warrantied all materials and labor. It took 3 1/2 months to fix. The tractor's back half was completely disassembled and the trans/rear end housing replaced. The dealer got $6,000 for doing the warranty work but they said it would have cost me about $8,000 if warranty would not have covered the damage. Kioti also stated they were performing a company wide recall of the hardware kit and replacing it with longer hardware. Another note; Thread locker is not used from the factory, nor was it used upon final assembly at the dealer. It was explained to me that the use of thread lockers is up to individual technicians and is not mandated.

Finally: I think it is important to add a CYA note here. I had checked and re-torqued all fasteners associated with BH the day before the failure at 20hrs. I put 35hrs on the machine in 3 days. My dealer tech was at my house 1 hr earlier on the day of failure for an emissions issue with the tractor. He seen what I was digging with the BH using the 12" bucket, and how I was doing it. He stated that is what the unit is built for. This cleared me of any "user abuse" accusations. I also took plenty of pictures of the tractor failure while it was still in position of use, as well as the ditch depth and material being dug when the failure occurred.

To the OP: I hope this info gives you some ideas as to what and why the failure occurred. I used to have a bunch of pictures and diagrams of the parts and situation but i don't anymore. Good luck sir.

Steve

Good story and good information for everyone. Issues like this have happened to other manufacturers. Cub Cadet installed many loaders on their 27HP and bigger machines back in the late 1990's using short bolts going into the engine block. This error caused the engine blocks to crack in the bolt mounting area. Cub Cadet had to make a new reinforcement plate kits to help support the loader mounts. I had to replace all those mounting bolts on my tractor. I found this out by having the bolts loosening up. What I did was to measure the depth of the bolt holes and used the longest bolts possible to hold my loader arms on with.

 

[blue1jassid]

Hi All,
I would like to provide an update on the transmission case cracking on my Kioti NX4510. Let me start by saying that if you plan to buy a Kioti NX series tractor and use a backhoe with it ... DO NOT BUY A KIOTI! ... until Kioti improves how the backhoe is mounted. Please allow me to share the details:
The transmission case cracked for the first time in early April of 2019 and I told the dealer of it about April 11. The initial leak caused me to limit use of the tractor because of the difficulty of filling the hydraulic system with the backhoe attached. The leak became steadily worse to where by June the tractor was essentially unusable due to the amount of hydraulic fluid being lost and the difficulty of replacing fluid. The tractor was finally repaired in late July. Thus the tractor had limited availability for FOUR (4) MONTHS through the high need time of spring and summer.

The transmission case cracked, a SECOND time, on Monday October 7, 2019. (I ordered the tractor on October 22 of 2018.) The tractor was not repaired and ready for return to me until December 6, 2019. Thus, I lost another TWO (2) MONTHS of use. In total, during my first year of ownership, I had impaired or lost use of the tractor for 6 months half the time I owned it.

Kioti has NOT changed the backhoe mounting system in a manner that I believe will provide reliable backhoe operation vis a vie the transmission case. The only change Kioti made to the mounting system was to add two more bolts through the mounting bracket into the transmission case. I researched how John Deere, Massey Ferguson, Myanmar, and Kubota attach their backhoes to their tractors. They all use what appear to be five or more inch wide, half inch or more thick, forged steel plates to carry the load to the axle housing just inside each rear wheel. The mounting to the axle housing is NOT by bolts into the housing but rather by bolting forged steel around the axle housing. Consequently, the 2" or greater diameter tool steel axles and the housing are taking the stress from backhoe operations not a few (4 initially and now 6 in my case) bolts into a 1/2" casting that is only about 10" wide between bolts. By mounting the backhoe to the axles, the other brands are creating a base greater than 48" wide to oppose the torque generated by backhoe operations performed at an angle to the long axis of the tractor.

Yes, per the factory, the backhoe brackets are to be mounted, as mine are, to the cast transmission casing. I talked to several people in the farm implement manufacturing business concerning mounting the backhoe into the transmission case. They all agreed that the transmission case cannot hold up for long if the backhoe is operated at an angle to the long axis of the tractor. The reason can be found in Kioti's advertising. Kioti says the Kioti KB2485 backhoe mounted on the Kioti NX4510 has a reach of 136.1 inches and a breakout force of 3,748 pounds. Multiplying this out yields 42,508.6 foot pounds of torque on the mounting system when the backhoe is operated perpendicular to the long axis of the tractor. Restricting operations, something the Kioti manual does NOT do, to 45 degrees or less relative to the long axis of the tractor, would reduce the torque on the mounting brackets and, hence, the transmission case to 21,254.3 foot pounds. The people I talked with thought even that number is likely to be too much for the transmission case to withstand over time.

Kioti service may be suspect beyond the long delays I experienced in getting my tractor repaired:

On October 22, 2019 I called Kioti痴 Customer Service Administrator because a high cost repair code (HCRC) had yet to be issued (per the local dealer) and under Kioti痴 policy a new transmission case could not be ordered and shipped from Korea until an HCRC had been issued. The Customer Service Administrator said that he could neither review nor change the policy. When I told him that anyone considering purchasing a Kioti tractor should know of the delays I encountered and the rigidity of the factory in requiring an HCRC, he hung up on me. Later, he lied and denied hanging up on me.

I forwarded to the Customer Service Administrator some of the correspondence between me and the local dealer. He blocked my URL, denied doing so, then, subsequently, restored the URL.

Before I got my tractor back, I had a long discussion with the dealer. The dealer said that the transfer case issues were caused by my improper operation of the backhoe and that the factory may no longer honor my transmission case claims due to backhoe operations. The power train has a 6 year warranty with no exclusions that I can find. I can find no limit to the operation of the backhoe in the backhoe manual that would make anything I have done, primarily digging out stumps and trenches for conduit and drainage, an 妬mproper operation.

Looking forward, I won稚 start using the 途epaired tractor with the backhoe until the frost is out of the ground, probably early April. I have a whole summer痴 worth of work, work that should have been done last summer, ahead of me in addition to what I had planned on doing this summer.

 

[JimR]

You may want to look into adding more support by running arms up to the loader arms and any other bolts area where you can put in another cross brace. Contact a lawyer if they stick it to you. I'm still waiting for a $2100.00 refund for warranty work that should have been covered. I'll be looking into that refund this week. If I don't get it, i will be filing a lawsuit against them. Their lawyer cost will supersede my refund tenfold.

 

[WoodDuck]

Sorry to hear about your experience with this, but I'm glad you posted it for us. Makes my decision a lot easier. I bought a new NX5510HST last year, thinking I might get a backhoe attachment later on. I've now decided against getting one at all. I have other 3 point implements that need to be ran at times, and getting the backhoe back onto the tractor after taking it off looks like a royal PITA from the videos I've seen. There's also the cost; I can rent an excavator or large backhoe several times for the $7000-$8000 my dealer wants for the backhoe attachment, and either one would work circles around a CUT backhoe. Some people have need of a digging machine on a regular basis, so renting something very often becomes cost prohibitive. If I ever decide to get another piece of equipment for regular digging, I'm thinking a used 4wd backhoe is the way to go for me. Excavators are way more $$$ in most cases, and they're also painfully slow to drive from one point on my property to another. That ~$8000 for a backhoe attachment would be better used as a down payment on an additional piece of equipment in my case I think.

 

[The Fred]

Curious how hard you use the hoe?

 

[countrybumpkin]

I’ve used the heck out of mine and haven’t had any issues.

 

[SGreene]

Thank you for your well written follow up report. I have been hesitant to use my backhoe since my second damage repair. I have found that those who have had this problem are owners of 2018 machines and newer. I wonder if Kioti made a metallurgy change in the trans casting?