Jinma 284 Trans/Powertrain Troubleshooting Help

[gpmorin]

Hello All,

I'm looking for some help troubleshooting transmission/4WD/powertrain issues with my Jinma 284. First a little background.

A couple years back, I had the right front wheel separate at the axle. I pulled it apart, did some digging around here and the web, and determined the outer stub axle sheared - most likely due to 4WD engaged on hard surfaces. I bought the tractor used, however some of the blame is mine :ashamed:. I got the parts and repaired it. All seemed fine for some time.

Now the current symptoms. One of the uses is to move bags of heating coal from the truck to where it is stored. During a run this past fall, I noticed grinding/chunking in that same wheel. I do use the 4WD to get onto hard surface, then usually :ashamed: pop it out of 4WD. When not in 4WD I don't remember any issue. I also use for clearing snow (rear mounted blade, loader when needed). I often have it in 4WD when clearing snow. I have noticed the 'clunking' issue when moving at a good clip (2nd gear) while dragging the plow. I don't remember if this is occurring only in 4WD. Now that on slippery ground, I notice clunking coincides with the right rear wheel spinning, and the left rear not spinning - even though the tractor is in 4WD. In the course of moving snow/sliding around, I put forward pressure on the 4WD selector (forward = 4WD) and felt grinding/slipping.

I'm not sure how extensive my repairs will be, and am looking for ideas on what may be happening. I suspect I'll be doing that right front stub axle again. It almost felt like a gear/spline broke in there and occasionally gets in the way or slips. I'm not sure why one rear wheel is not in 4WD even when selected, and what the relationship is to the right front wheel clunking. Any ideas on what else might be going on?

Any thoughts/help is welcome!

Thanks for reading,

Gpm

 

[RonMar]

First off 4WD is only actually 2WD. These front and rear have open differentials so a wheel that can slip will spin while the other wheel justs sets there allowing the spinning wheel to suck up all the torque. You have a locking rear differential, lever down by your right heel. Lift it while one of the rear wheels are spinning and when it engages it will lock the rear axles together which will give you 3WD. Only use it to get unstuck...

As for the front, depending on what parts you replaced it could be one of the internal clips let go and has allowed some gap in the bevel gears and when you put it under load it starts skipping gears and clunking. You will have to pull it apart to see...

 

[gpmorin]

First off 4WD is only actually 2WD. These front and rear have open differentials so a wheel that can slip will spin while the other wheel justs sets there allowing the spinning wheel to suck up all the torque. You have a locking rear differential, lever down by your right heel. Lift it while one of the rear wheels are spinning and when it engages it will lock the rear axles together which will give you 3WD. Only use it to get unstuck...

As for the front, depending on what parts you replaced it could be one of the internal clips let go and has allowed some gap in the bevel gears and when you put it under load it starts skipping gears and clunking. You will have to pull it apart to see...

RonMar - thanks for your response. Now I understand the rear end better and that lever. I never tried engaging it with the tractor moving, or without the clutch disengaged. As far as the front end, it's on my ToDo list and will come apart for inspection/repair in the coming months.

Thanks again for the reply!

Gpm

 

[RonMar]

Like the 4wd lever you usually have to be moving to engage it. It uses two pieces called claws or pawls. They look like a 6 piece pie with every other piece missing. There is one on each chaft facing each other They are straight cut so the two shafts need to be rotating at slightly different speeds to get the 3 pie pieces on one to match up with the 3 missing pieces on the other so they can slide together. The 4wd mechanism and the difflock use the same pieces.

The clutch has nothing to do with either process, just pull on either lever while rolling to engage...