Largest JD with Hydrostat??

Dagwood55 · Aug 23, 2014

I now have a JD 4200 with 800 or so hours with front loader, tiller, brush hog and other stuff. I need to go to a larger tractor
because I've purchased more land to bush hog. But I love my hydrostat and would like to have it on a larger tractor, so..

Whats the largest JD with hydro?? And why would I not want it on a larger tractor??

thanks,

arlen4720 · Aug 23, 2014

The biggest current production is the 4066R and the 4066M with 66 engine HP. 2013 and before, it was the 4720, also with 66 engine HP.
The hydro works great on the 4720 as far as I can tell. I've had mine for 2 and a half years, and have just over 500 hours on it.
Just make sure it's big enough for you. You would have to jump up to a 6R series with an IVT tranny to get something with the similar feel of a hydro in a larger machine.

Fallon · Aug 23, 2014

I think they drop the HSTs in the 60+ HP range due to efficiency. At that HP the 15% performance hit & associated extra fuel costs compared to a geared tranny hurt.

SDT · Aug 25, 2014

As Arlen has already posted, the 4720 and it's replacement the 4066 are the largest HP hydrostats available.

Hydrostats are very convenient but also very inefficient (and expensive). They have not been successful in higher HP tractors in the past.

SDT

Fallon · Aug 25, 2014

They do make big HSTs for construction & mining applications, so it is possible.

My assumption of the thought process:
If you have big HP in a tractor, you are doing ag.
If you are doing ag, you want the most efficient machine possible as you are spending all day in big fields going in mostly straight lines.
Efficiency trumps ease of use.

arlen4720 · Aug 25, 2014

Fallon said:
They do make big HSTs for construction & mining applications, so it is possible.

My assumption of the thought process:
If you have big HP in a tractor, you are doing ag.
If you are doing ag, you want the most efficient machine possible as you are spending all day in big fields going in mostly straight lines.
Efficiency trumps ease of use.

You are right. No sense in having a hydro when you are going round and round in a field all day. Hydros cost more, and use more fuel...everything you DON'T want for a field tractor.
Hydros can be, and are, built for high HP applications. A 200 hp skid loader would be a good example.

buickanddeere · Aug 25, 2014

No problem using hydrostatic on a bulldozer which is a heavy draft application. There must be some losses?
Then again there is the swash plate hydrostatic system and the automotive style with a fluid converter Nd planetary gear sets. Some lockup torque converters in service .