any downside to hst?

[ridgerunnerinwv]

Is the 4400 a powershift?

soundguy

Soundguy,
My JD4400 is not a powershift,it is a hydro.

 

[MadReferee]

Just flipping thru a couple NH manuals, and some JD and cat HE manuals.. i see lots of cat and JD equipment with torque converters in the tranny.. I don't see alot of torque converters on many tractor HST trannies.

Perhaps we are being a bit loose in what is a 'hydro' trans.. etc.

Soundguy

I'm just going by the product literature. The dozers are all advertised as having "hydrostatic" tramsmissions. Maybe someone out there that has actual operating experience can chime in with a more definitive answer.

 

[dirtworksequip]

The Caterpillar track skidsteers have dual closed loop hyd. axial psiton pumps that drive a hyd. motor on each of the drive sprockets. Excavators are set up about the same way with a drive motor on each track sprocket,but has an open loop system to run the hoe functions. The hystat dozers have two variable-displacement axial piston pumps mounted tandem-style to the flywheel and a pump on each track.
Whats nice about the hystat heavy equipment is when you go to nuetral they STOP. If the CUTS had the same setup as a CAT dozer they would truely be an awesome machine.

 

[Soundguy]

Sounds like some new equipment...( something we don't have an abundance of.. ) I'm guessing the 'hystat' is the big difference... Much of our older iron is torque converter driven.. save for a few that actually have hydro pump / motor drives.. like some old rollers.. etc.. and excavators.. etc.

I know our cat pans have torque converter style trannies.. very similar to a car tranny... choose a gear, and then you have an accelerator pedal.. etc.

Mad ref.. I'm guessing you don't count pans as real heavy equipment then right? even the 23 yard and 31 yard jobs..??

Soundguy

 

[Brad_Blazer]

Let me add my 2 cents to the efficiency thing. True fuel efficiency is not hours/gallon, it is work accomplished per gallon. If an HST tranny burns 10% more fuel to put a given amount of power to the ground but saves 15% in economy of motion (i.e. the operator can keep the wheels turning at the desired speed/direction at all times) it will be more fuel efficient. That doesn't even factor in the labor saved. Also if it runs fewer hours to accomplish the same work the periodic maintenance costs will come down.

By the way I have and prefer gear tractors myself. I like the feeling of knowing just what I've got between the motor and the ground. Reading this thread I could probably get used to a HST but I don't mind a little extra excercise. Lots of people spend time and money working out. I prefer accomplish something when I work.

Brad

 

[N80]

I think it has been mentioned in passing, but the OP asked about the downside to HST. I think the benefits have been well explored and for the most part there aren't any huge downsides except cost. And more specifically cost vs hp. I'm not talking about hp loss vs a geared tractor. I'm talking about what amount of hp can you get in a geared vs an HST for the same amount of money. That's where you get into a pretty big difference, and if you need the hp, a pretty big downside.

I have a Kubota L4400. As basic a geared model as you can find. No GST or shuttles or even synchro (theoretically you have to stop before shifting...I can shift on the fly if things are timed right.) It is a 45hp tractor. I wanted the most powerful tractor I could get for under $20,000. The L4400 is it.

Take a look around and see the max hp you can get for $20k in an HST machine. It is considerably less.

The dealer gently pushed me towards an HST machine. I think he showed me a 3400 at a similar price and a 4130 at considerably more. I wanted, and as it turned out, need the additional hp.

So don't forget that there are some folks who might enjoy and benefit from HST that simply can't fit it in our budget and still get the power that we need.

I also happen to be one of those types who see no particular use in power windows and I currently despise the automatic transmission in my F150. Maybe I'm a control freak, but I prefer manual trannies in my vehicles. As soon as I'm done with this F150, I'm going to find something with a manual. Maybe an F250.

As far as operating the L4400, I'm super comfortable with it and can do extensive loader work without ever thinking about shifting or even look down to shift. Of course, my 43 year old left knee is sore after doing a lot of loader work. No arguing that. But for mowing, BBing, etc. No knee pain.

The other thing that affected my decision was repairs. I have a B-I-L with a complete tractor shop 1/2 mile down the road. He repairs all his big tractors himself including engine and tranny rebuilds. But he has never cracked anything but a full manual. With that in mind, plus the dollar to hp ratio, a geared tractor is perfect for me, especially since I'm a manual kind of guy anyway.

 

[Soundguy]

Hmm.. downsides? Hard to come up with any true disadvantages.. I can only think of ones where you are stuck because the trans has run out of oil.. like a blown line on a loader that sucks the sump dry.. or a blown cooler.. etc.

With a gear unit.. in an emergency.. you could keep going. I guess the old railroad track analogy... with a gear unit, you can jump jimmy starter while in gear and make a gear unit walk across a track.. oil or no oil in the tranny.. etc.

Again.. not real mainstream issues...

Soundguy

 

[john_bud]

There is a down side for HST's in the winter. (Real winter, not that stuff you guys in Florida have ! LOL!!!!) When it is below zero you have to warm up the tractor for a considerable amount of time to thin the fluid for the HST to be happy. At -30F, you need to warm it up about 30-40 minutes. I have blown the HST filter out multiple times in the past -- but not since getting the latest rev of the filter! However, the tractor still needs to warm up a lot longer than a gear tractor.

jb

 

[Soundguy]

Hmm... synthetic UTF??? may have a good real world app .....

Soundguy

 

[Hard]

besides cost, is there any downside to an hst transmission? are there any applications for which you would prefer a powershift or conventional manual?

No, not really.