Front end snapped-- bummer

thebudman · Jan 23, 2011

Bad news: I was using the FEL on my 254 Jimna/NorTrac while in 4x4 (ok-- I know its bad to do that, but I was in clay-like mud and thought there'd be enugh wheel slippage). I heard something snap in the front left wheel. Thinking this was bad, I limped it back to the garage in 2wd. However, while en route, the left front wheel locked up. I put in in reverse and managed to get it to move freely, rolled for another 50 yards or so, then it locked up again. Putting it in reverse freed it up and I was able to get it in the garage.

My question now is: what did I break, how complicated is it to fix, and, if we ID the problem, how much will the new part be? Any why did it break in the first place? Any suggestions?

bluechip · Jan 23, 2011

Ouch, being it locked and released, I'm guessing gear teeth. In our expereince withe Jinma tractors, the differential gears were the ones to go, but it is also possible something in the outer drive went. Sounds like time for some exploritory surgery. If you heard it on one side, I would start there, take the final drive, open it up off and have a look. Before you do, you can check the diff by raising the front end, with 4wd engaged, one wheel should roll backward when the other is turned forward, then when out of thear, hold one wheel stationary while turning the other and see what it feels like, you should be able to feel the broken gears on the bad side or in the diff.

Affordable · Jan 23, 2011

Chip is right,you will need to figure out what side or what gear is damaged,Once you get it checked out let me know,we have all the parts or depending on how mechanical you are we have assemblies,that are ready to just bolt on

Tommy

3RRL · Feb 16, 2011

budman,
Did you get to the bottom of the problem yet?
Tommy and Chip have given you a good direction to follow.

I had the same thing happen to me under exactly the same conditions, except on my Kama tractor.
I heard a "crunch" and one of the front wheels lock up. Lucky for me the problem turned out to be in the final drives. Turned out that 2 small bevel gears were stripped, and probably some of the broken teeth got wedged between other gear teeth. My damage, to be specific, was to the bevel gears attached to the front axle shaft, and the vertical one in the front drive casting (the top one, where the 2 gears engage). It turned out to be an easy repair...just scary at first since I had never opened the front drives before.

Even if it is not those bevel gears, Tommy will surely have parts for you.
Here is a link to the repair on the Kama tractor:
Kama 554 Front Drive Repair
The front drives are similar enough and there are lots of photos to help you through.

This link is something I did to repair my wife's 4WD on her Jinma 284:
4WD Repair on Jinma 284
That one shows how I fixed the front drive shaft engagement.
I don't know how the dealers feel about that repair, though?

Rob-

Gods Country · Feb 16, 2011

Why do you say it's a bad idea to use the FEL while 4WD is engaged?

greg_g · Feb 16, 2011

Gods Country said:
Why do you say it's a bad idea to use the FEL while 4WD is engaged?

That comment is really most applicable to the Jinma 4wd 200 series tractors. Bigger Jinmas (300 series and above) - and other Chinese tractor brands in general - don't have that problem. I regularly slammed into dirt/gravel/rock piles with my TS354C in 4wd without issue, except for the ruts I dug into the soil or gravel. That said, I don't think I'd use that particular technique on asphalt or cement.

//greg//

Rich Waugh · Feb 16, 2011

God's Country,

The reason for not using the loader when in 4WD is that the additional load of a bucket full of wet dirt or rocks or something else pretty heavy puts a high load on the relatively weak front drive components. As Greg noted, the 300 series Jinmas have much heavier front drive assemblies than the 200 series does, but then, they also typically have bigger loader buckets. I'd say it still pays to be cautious.

The front and rear drive systems are lined by the transmission and transfer case and when the loader bucket is heavy the the front wheels now have more traction and the rear wheels have less. Under the wrong circumstances you can load the front wheels so much and simultaneously unload the rears to the point that almost all the engine power is being absorbed by the front drive system and overload it to the point something snaps.

I do use my loader while in 4WD but I am careful not to ram the bucket into immovable objects or to get the tractor into a situation where the front wheels have good traction and the rear wheels can easily slip. So far I haven't had any such problems with my 300-series Jinma, but it only takes a moment's carelessness or ill-considered exuberance to wreck something. You can easily guess how I learned this lesson, right?

Rich

David Devuono · Feb 16, 2011

Its obvious from the thread that the front axles are weak. But in general you have smaller tires which require less torque to spin on the Front and the diffs are open so unlike a rear end that when locked up will put all the power to the wheel with traction, this does not happen in the front. Anyways it cant hurt to disengage when using the loader but the benefit of 4x4 is that you do not have to ram the dirt pile, just slightly tilt the bucket while loading to place weight on the front drives and the bucket fill better. To not use 4x4 with a loader when digging in dirt makes little sense. (unless of course you know it will break your tractor)

Gods Country · Feb 16, 2011

I'm sorry to hear that one must be so cautious when loading on these tractors.

greg_g · Feb 16, 2011

David Devuono said:
But in general you have smaller tires which require less torque to spin on the Front and the diffs are open so unlike a rear end that when locked up will put all the power to the wheel with traction, this does not happen in the front.

What you say has merit - IF - there was a center differential. I have not by any means seen every Chinese tractor ever made. But those I have seen and worked on do NOT have center differentials. It's a straight mechanical connection, no slip clutches, nothing. So with the 200 Series 4wd Jinma, this issue is no more complicated than an under-built front drive assembly - a problem that can be avoided by not using 4wd during loader operation

There is no admission from the manufacturer on this, and no fix (that I know of) in the works. It's simply a School of Hard Knocks lesson learned by many who actually own and operate a 4wd Jinma 200 Series tractor.

//greg//

Diamondpilot · Feb 16, 2011

Gods Country said:
I'm sorry to hear that one must be so cautious when loading on these tractors.

Its simply a risk. I have 850 hours on my Jinma 284 and 500 or more of them hours are using the FEL in 4x4 either loading dirt/gravel or skidding/lifting logs. I have not had any issues but if and when it does I will fix it.

I know the risks.

Chris

Gene :^) · Feb 16, 2011

My 1999 Nortrac NT254 (Jimna) is holding up fine and I almost never take it out of 4wd. I load the FEL in 4wd all the time.

I never run the bucket fast into whatever I am loading. I always approach the pile, stop, put it in 1 low or 2 low, and crawl into the pile slow. This slow push into the pile allows me time to run the hydraulic control for the bucket to get the best fill. I fill the bucket heaping high then shift back to high range and go.

Gene :^)

RonMar · Feb 17, 2011

Yep, slow and steady works for me also. It gives me time to optimize the bucket, and also to stop if the bucket/tractor stops, before the drivetrain gets overloaded. I think the breakages mostly occur when things repeatedly get stopped suddenly(wheels) while the bucket is under load. Weight = Traction, that is one reason these tractors have so much pulling force for their size. They are heavy... You get that bucket into/under something that dosn't want to move, and load up and stall the front axle, you will find the weakest link in the drivetrain. It is by name and design a LOADER, not an excavator or bulldozer. In my experience, the larger in scale you get, the more important it is to have the right tool for the job

IE: back in and tearup/loosen with the backhoe, then scoop out the loose bits with the FEL. That works well for me with this particular tool.

Good luck with your repairs.

erj · Feb 18, 2011

I believe that another consideration when using the FEL for heavy moving is providing a rear counter-balance to try to keep as much weight as possible on the rear wheels. Whenever I am going to do some heavy FEL work, I put the backhoe on.
RonJ

Bob Rooks · Feb 18, 2011

erj said:
I believe that another consideration when using the FEL for heavy moving is providing a rear counter-balance to try to keep as much weight as possible on the rear wheels. Whenever I am going to do some heavy FEL work, I put the backhoe on.
RonJ

I know your intentions are good but in essence you are only adding more total weight to the tractor and the front axle - the fulcrum point. In essence, you are possibly overcoming design and axle limitations to get the task done.

IMHO.

greg_g · Feb 18, 2011

Bob Rooks said:
In essence, you are possibly overcoming design and axle limitations to get the task done. IMHO.

But not in the opinion of the tractor manufacturers. Got my new John Deere Monday, and have been going through the various operation manuals. They dedicated a surprising amount of space to ballast. Three different front loaders are optional for this tractor. Progressively heavier loaders require progressively more ballast. And John Deere is addressing just the weight added by the loader. Although unstated in the manuals, the recommended ballast weights/distribution probably also considers the lift capacity of each loader as well. In each case, the manual recommends optional rear wheel weights or filled tires. Depending upon how much weight that represents, they go on to give a specified amount of additional weight be put on the three point hitch. This is in the form of a purpose built ballast box, or an implement of equivalent weight.

And all this additional weight is just to compensate for the loader itself. Empty. Granted, ballast adds to the gross weight. But it's the amount and distribution of that ballast that actually relieves stress on the vulnerable front of a loader equipped tractor, ostensibly by shifting the center of gravity toward the rear.

//greg//

Gene :^) · Feb 18, 2011

I always have an attachment on the back end when lifting anything more than fluff with the FEL.

90% of the time it is the backhoe but sometimes the Box Blade or Chipper.

Otherwise the tractor is so light in the back end that the rear tires have close to zero traction and a sudden stop in 4wd with the FEL loaded and up high can lift the rear wheels off the ground.

2wd is useless with a heavy load in the FEL and no rear attachment because you just spin the tires... and forget about stopping on any kind of incline. You will just lock the rear tires and slide out of control, I have done it. I had to drop the FEL to the ground to stop me.

Gene :^)

erj · Feb 19, 2011

greg_g said:
Granted, ballast adds to the gross weight. But it's the amount and distribution of that ballast that actually relieves stress on the vulnerable front of a loader equipped tractor, ostensibly by shifting the center of gravity toward the rear.

//greg//

Thank you, Greg.
That is the point that I was trying to make.
RonJ

Bob Rooks · Feb 19, 2011

greg_g said:
And all this additional weight is just to compensate for the loader itself. Empty. Granted, ballast adds to the gross weight. But it's the amount and distribution of that ballast that actually relieves stress on the vulnerable front of a loader equipped tractor, ostensibly by shifting the center of gravity toward the rear.

The FEL mounts in approximately the center of the tractor. The support and reaction framework extends to forward of the front axle. The loader bucket is in front of the front axle, thus, the front axle is the fulcrum point. Any weight added to the rear is just excess baggage ("counterweight")(aft of the rear-wheel fulcrum point) until a load is applied to the FEL bucket, which in turn transfers a portion of that weight to the front axle in compensation. No weight will get transferred to the rear wheels during FEL operations unless you relocate the the FEL attachment points to the rear of the rear wheels. Thus the reason for the counterweight behind the rear wheels.