Getting power to the wheels

[Mrwurm]

I recently purchased my first hydrostatic compact (NH TC30 30hp). I have found that when pushing the loader bucket into a pile I can spin all four tires in low range. In high range or medium I can't spin the tires even in two wheel drive. I have tried using the smallest amount of pedal pressure all the way up to pushing it down all the way (which stalls the tractor). I am not too impressed. If I have to shift to low range each time I fill the bucket and then shift back to med or high range for transport, whats the point in having hydro?

Oh, maybe I did'nt explain that well. What I mean is that I can't get enough power to the wheels to fill the loader bucket in med or high range. The tractor just sits there. No spinning. No forward motion. Low range handles it just fine.

Am I expecting too much from a hydrostatic tractor? I thought that if I applied very light pedal pressure I would get an infinitely low ratio from the transmission.

Jerry

[TerryinMD]

Mrwrum,

How are you attacking the pile?

If you are dropping the blade and just driving straight forward without curling and lifting the bucket, this may be the problem.

In the JD FEL manuals, they have a decent explanation on how to use the FEL to pick up materials. It takes a little practice, but once you understand the principles you should have no problem. I sometimes forget to let up on the forward motion pedal for my HST and the wheels will slip while picking up material.

I always use low range on my tractor (it only has two ranges) with 4wd when using the FEL. More power is transferred to the wheels.

Terry

[Woody1]

there is a fine art in scooping up materials with your bucket. Wheel spin is a good thing! use the bucket hydrolics to "dig" your way into the pile. Just movce it around, apply the right amount of wheel torque to the ground to move yourself forward. Keep at it, dont get discouraged. Takes a lil gettin used to. In high gears, you cant get that much "umph" to get into the pile. i only got 2 speeds, and i ALWAYS go into the pile in low, and carry the load in low.Carry your load low as well. You shouldnt5 be going to fast with a full bucket. You will sometimes start bouncing when u have a full load, and it can get carried away. Remember, you are on a UTILITY tractor, not a loader that loads dump trucks! Take your time, you will get used to it.

[Kodiak]

You didn't explain what type of material your working with. Is it undisturbed native soil or an old pile that has settled and densified. If so try lifting your loader arms and curl your bucket under. Then backdrag from the top of the pile or high up on the bank. This will break up the material, so you can the drive into the pile with the bucket leveled. As you start to lose traction, or stall out, just curl your bucket up and start raising the bucket at the same time. Just remember its a lot harder to load dense or solidified material than loose.

[paccorti]

Jerry,

This is completely normal. All HST's have a relief valve to protect the HST pump and motor. In any transmission type device you have a trade off between effort (torque) and flow (speed). Just because you can vary the speed between 0 and top speed in high range does not mean that you can generate the maximum torque at low speed (your relief valve pops). If that was the case why bother having the medium and low ranges, right? A gear tractor (in high range) would just... stall.

There are some tricks to help fill the bucket without shifting down. Curl the bucket back and begin to lift the loader arms slightly as motion ceases as you push in the pile. This will help you fill the bucket far more. You probably still need at least medium range for that. I routinely shift into low while digging and (after backing up) switching into high while stopped.

Peter

[Woody1]

i had forgotten how long ago i was same way with getting used to loading the bucket till this thread

[Mrwurm]

Thanks to all for all the advice. The issue that I have been concerned with is not the actual act of loading the bucket, though I admit I'm new at it and can use some advice. What I have been confused about is the action of the hydrostatic trans. When I push the bucket into a pile I expected one of three things to happen:

1) Tractor moves forward
2) Tires spin
3) Engine stalls

What I did not expect is that the tractor would just sit there in high or med range with hydraulic fluid cycling through the relief valve.

4) Tractor sits there doing nothing

My previous tractor was a gear drive and I guess I was expecting the hydro to behave in the same fashion. Peter made a good point in that if the tractor behaved as I thought it would then what would you need three ranges for?

Jerry

[Rick Jay]

Hi Jerry,

It does take a bit of practice to fill the bucket. I'd just add that the hydro pedal is not a throttle. Pressing harder on the hydro pedal is analogous to shifting to a higher gear. To get maximum power, you want to be in Low gear on the hydro, light pressure on the pedal and lots of throttle.

If the tires lose traction before the relief valve opens, then the tires will spin.

It takes a fair amount of power to drive the bucket into a packed pile of dirt, so loosening it up first using the bucket lip is a good idea.

I think this is one of the reasons toothbars are so popular on compact utility tractors.

~Rick