Dozer Question

[midTN_Brangusman]

Was doing some clearing today and my left track started locking up. It would lock up going forward then unlock going in reverse. Would work fine for a while then locked up again. Any thoughts? It is a John Deere 850J

 

[jltrent]

How is the undercarriage, are the idlers and rollers good? Any pads bent and is everything in line? If both tracks were locking then might be some concern with the transmission, but only one side you maybe alright there.

 

[midTN_Brangusman]

Yes sir undercarriage, idlers and rollers look good. That is correct just one side locking up. I just spoke with a dozer mechanic. He is going to take a look Saturday. I'll update on the culprit. Hopefully nothing big

 

[chevytaHOE5674]

J Series is hydrostatic so no steering clutches or brakes. That leaves trouble in the double planetary final drive (drop the oil and check for any shrapnel) or trouble in the hydrostatic system (if that's the case you need a good understanding of the hydraulic system and some good gauges).

If something in the undercarriage came apart and was physically stopping the track you should hear the hydraulics going over relief.

Either way I would park it until fixed.

 

[sstterry]

Yes sir undercarriage, idlers and rollers look good. That is correct just one side locking up. I just spoke with a dozer mechanic. He is going to take a look Saturday. I'll update on the culprit. Hopefully nothing big

Deleted because Chevytahoe knows more about these than me.

 

[ClinchValley86]

Was it making any kind of noise out of the ordinary?

 

[midTN_Brangusman]

Was it making any kind of noise out of the ordinary?

I didn't notice a noise. Would catch every once in a while. Then wouldn't go forward on the left track but would go backwards. Worked fine after that for a while then left track completely locked up.

 

[ClinchValley86]

I didn't notice a noise. Would catch every once in a while. Then wouldn't go forward on the left track but would go backwards. Worked fine after that for a while then left track completely locked up.

I hope it's nothing crazy.

 

[jltrent]

I didn't notice a noise. Would catch every once in a while. Then wouldn't go forward on the left track but would go backwards. Worked fine after that for a while then left track completely locked up.

Scary as I hope something simple as a JD850 is not small. A neighbor up the road has a JD750 and it is torn up more than it works. Right now it is beside the road with the engine out probably being overhauled.

 

[midTN_Brangusman]

I hope it's nothing crazy.

Me too!

 

[midTN_Brangusman]

Scary as I hope something simple as a JD850 is not small. A neighbor up the road has a JD750 and it is torn up more than it works. Right now it is beside the road with the engine out probably being overhauled.

Turned out to be a broken gear in the final drive. Parts and labor $8500.

 

[chevytaHOE5674]

That was my guess.

Hopefully your replacing the complete final drive?

 

[Nesikep]

Turned out to be a broken gear in the final drive. Parts and labor $8500.

that's quite a bill!

 

[chevytaHOE5674]

If your not replacing the whole thing, make sure to check the pinion bearings. They are usually the culprit causing the inner sun shaft to break.

 

[midTN_Brangusman]

If your not replacing the whole thing, make sure to check the pinion bearings. They are usually the culprit causing the inner sun shaft to break.

They changed the bearings also

 

[midTN_Brangusman]

That was my guess.

Hopefully your replacing the complete final drive?

No would be over 25k

 

[chevytaHOE5674]

Once I asked that question it clicked that 8500 bucks isn't nearly enough to completely replace a final. Haha

For the cost of repairs changing the final drive oil more often is cheap. Inspect the old oil closely. If you notice glitter the bearings are on their way out. If you catch it early you can replace the bearings before breaking parts.

If I was a betting man I would say the other side won't be that far behind unfortunately.