What to look for in used 4120

[coloradotrout]

Any major flaws with a 2010 4120 hst?

If not, what should I look for on one with 750h?

What's a good price? No fel, not attachments.

 

[bmaverick]

The JD4120 is built like a tank. And the weight of 4000-lbs with the machine does reflect that too. Lots of heavy duty casted parts as well. A big and heavy engine in a small package.

If your concern is about the weight, the 3xxx series has the 3046R that can hold it's own as well.

The real concern is, parts availability and costs. The true JD made in house engine is more unique and custom. Years from now, those parts will be a premium. IF you picked a JD with a Yanmar engine, parts are more popular in the aftermarket channels right up to full engine repower replacements.

So, if your looking to have a tractor for life, be sure to know what you are getting into.

 

[coloradotrout]

Thanks. Is "tank" here a good thing? Generally I would want that. I have a 4100 cut and don't like the newer 20hp light weight models. The proprietary parts does sound concerning. Is that engine likely to go 4K hours? The one for sale here has 750.

 

[bmaverick]

Thanks. Is "tank" here a good thing? Generally I would want that. I have a 4100 cut and don't like the newer 20hp light weight models. The proprietary parts does sound concerning. Is that engine likely to go 4K hours? The one for sale here has 750.

Tank is a good thing for a solid strong machine. It's bad when you are in areas requiring a weight limit like crossing a home made creek bridge or driving next to a septic field. Also bad when it's sloppy outside going down hill.

I know the Yanmars go for several K hours before an overhaul. Some even out into the 6K to 12K hours. Depends on the use and abuse.

 

[coloradotrout]

I understood you that the 4120 is not a yanmar. Thoughts on it's longevity?

 

[redman135]

Call JD and ask what the design life of the engine is.

 

[coloradotrout]

Is there high confidence JD design life is a good measure?

 

[bmaverick]

Is there high confidence JD design life is a good measure?

Unknown. I've only owned JD machines with Yanmar engines, and now a Yanmar with a Yanmar engine.

Some, not all JD engines are used in other industries like Industrial and Marine. Should the 4120 engine have the same offerings, then it would be good to buy. This way, parts would be available for a mighty long time.

As the saying goes, don't be drawn in by the one-offs. You'll pay thru the nose in the long run.

 

[usmron]

I own a 4120 hat and I love it . Have grapple, bucket, forks. Use it all the time.I also have tiller, disk, spike tooth harrow, three pt spreader and MX 6 clipper from Deere. I did not want the yanmar, engine and wanted it built in USA. Mine has the Power Tech engine and the tractor was made in Augusta GA and wanted the three tier and not the four so it does not have the burn off feature which is what I wanted and got it the last year they built the three tier. Love it. Also my friend got the one that replaced it and lot of changes. The pedals are not heavy like on the 4120, mine are made out of same material like in the bigger tractors not flimsy like the ones they put on now.

 

[bmaverick]

I own a 4120 hat and I love it . Have grapple, bucket, forks. Use it all the time.I also have tiller, disk, spike tooth harrow, three pt spreader and MX 6 clipper from Deere. I did not want the yanmar, engine and wanted it built in USA. Mine has the Power Tech engine and the tractor was made in Augusta GA and wanted the three tier and not the four so it does not have the burn off feature which is what I wanted and got it the last year they built the three tier. Love it. Also my friend got the one that replaced it and lot of changes. The pedals are not heavy like on the 4120, mine are made out of same material like in the bigger tractors not flimsy like the ones they put on now.

Well, some of the engines were made US side and the rest in Mexico. And the PowerTech engines are very unique to themselves, thus, there really isn't any part interchangeability amongst engines. The engines are extremely proprietary. The 4120 was made only for 10 years and today has a totally different replacement. hmmmm

https://www.aiproducts.com/TECHBULLETIN/TM0014.pdf

 

[wolc123]

I own a 4120 hat and I love it . Have grapple, bucket, forks. Use it all the time.I also have tiller, disk, spike tooth harrow, three pt spreader and MX 6 clipper from Deere. I did not want the yanmar, engine and wanted it built in USA. Mine has the Power Tech engine and the tractor was made in Augusta GA and wanted the three tier and not the four so it does not have the burn off feature which is what I wanted and got it the last year they built the three tier. Love it. Also my friend got the one that replaced it and lot of changes. The pedals are not heavy like on the 4120, mine are made out of same material like in the bigger tractors not flimsy like the ones they put on now.

I bought a new 4120 in 2005 and it had been great. I am very thankful to have bought it when you could still get an American made , pre tier 4, JD power tech engine . JD has long had the best part support of any tractor manufacturer.

I am more confident in continued availability of parts for the power-tech engines than I would be for the Yanmars.

 

[RoyJackson]

I had a 4520...same engine as the 4120 with a bit more power and torque. During my research, and IIRC, these engines were used in other applications...marine and industrial...skidsteers too. Also, engine life was around 8000 hours (of course, that depends on regular maintenance.
Mine was a cold natured beast, but as long as I plugged it in (block heater), I didn't even need glow plugs. I bought the tractor with just over 2000 hours and sold it 4½ years later with around 2800 hours. Only reason I sold it is I want a factory cab rather than the Curtis cab on the 4520.
The Deere engine definitely had more torque then the current Yanmar powered tractors (no complaints about Yanmar though...of the 5 Deeres I've owned, 4 were powered by Yanmar)
So, I don't think you'll have any issues with the 4120 or parts availability.
My estimate on a reasonable price for a tractor in good condition and 750 hours would be $12K-$14K. Prices are somewhat dependent on location...higher in the NE, lower in the south