How much "slip" on your TC hydrostatic?

SacandagaBrad · Feb 11, 2004

How much \"slip\" on your TC hydrostatic?

Can any of you TC owners (I have the TC24D) put your machine in a postition where the wheels won't spin as you continue to give it power? I have had mine stuck where the wheels won't break traction and the tractor can't get enough power to the wheels to get out the situation. Doesn't matter if I'm wide open throttle and depress the hyro pedal all the way. I would think it should stall out rather than slip. You can definitely put a pull on the motor, but not stall it. Seems like if it just transferred a little more to the drive wheels, it would either walk out of the hole or start to spin, at which point you would try something else to get out. It is also annoying when trying to slowly push into a stiff bank of gravel to fill the FEL, it just gets to a point where it won't go any further yet the motor has more to give.

I checked with the dealer, he thinks the relief valve may need adjusting. He told me to keep an eye on and let him know, he could have a tech at the house any time. I'm just wondering if this is a normal "safety" feature built into the hydro system to protect the rest of the drive train. Do yours behave like this or can you get all your power to the wheels? I know if I had a geared model, low gear would just keep churning until you let up. I still like the hydro /forums/images/graemlins/smile.gif

Brad

Bird · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

Brad, my experience with Kubotas is that they could do the same thing if the range selector was in the high range. But if I shifted to the low range, it would spin the wheels. The only way I was ever able to get it to stall out, like you described, in low range was to hook the point of a plow (or ripper tooth of a box blade) under a good strong immovable root, then try to raise the 3-point to pull down on the rear tires to get maximum traction, and that was was able to get the relief valve to open instead of spinning the tires or killing the engine.

Now if you had a geared tractor, you'd do no better. Instead, if you couldn't spin the wheels, you'd kill the engine instead of opening a relief valve.

PineRidge · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

Brad I think Bird summed it up very nicely. My TC-40D will do the same thing in Range II. When you need to work go for Range I and a softer foot pressure.

JerryG · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

 Doesn't matter if I'm wide open throttle and depress the hydro pedal all the way. 
Some of the hydro people can say for sure, but if you push the peddle alway down you are in high gear so to speak. If you just barely press down on the peddle them you should have the most pulling power.

markie61 · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

I depends on the ground material, too. If it is muddy, I spin tires no problem. I was trying to push over a walnut tree on dry ground and it would behave as you describe. I think it is normal.
Mark

SacandagaBrad · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

( Brad I think Bird summed it up very nicely. My TC-40D will do the same thing in Range II. When you need to work go for Range I and a softer foot pressure. )

( If you just barely press down on the peddle them you should have the most pulling power.)

I know what you all are saying, I should have mentioned that I am using low range. And I have to continue to depress the pedal for more power and also thought that was equivilant increasing the "gears". If I only press it down say 1/4 to 1/2 way, it just sits there with a moderate load on the motor. I just imagined that I would be able to ease a bucket into the pile and depending on traction, either stall or spin. That, to me, would indicate I have applied all the available power to the wheels. Is that good for a machine? Probably not, but should be OK as long as you're not ramming it.

When the tractor is stuck, it would be nice to have that little extra that you know the motor has just from the sound of it. It is very frustrating to try to back out of a hole and not see any wheels spin and know there is more power that should be getting to the wheels. Usually I use the bucket to help it out, but this weekend found myself in a spot where I couldn't get the bucket into anything solid to push from. Had to get one of those wooden handled things to help it out /forums/images/graemlins/blush.gif

Brad

PineRidge · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

Brad in range I the majority of your power will be with light foot pressure not all the way to the floor. If I push into a pile in range I and don't downshift I will not break traction, but the HST will pull the engine down and stall it. If I push into that same pile and downshift at the joystick as my RPMs start to fall I can keep my momentum to completely fill the 72" bucket before backing out.

I had the same misconception of how a HST worked when I first got my rig. I thought more foot pressure meant more HP. When in actuality a lighter foot pressure will deliver the most HP to the wheels. I hope some of this has helped you a bit.

JerryG · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

The more you press down the less power you have. As it starts to bog down, the peddle should be eased up on.

slowzuki · Feb 11, 2004

Re: How much \"slip\" on your TC hydrostatic?

You mean to say torque to wheels not hp. Actually it is an interesting safety feature the relief valve.

On a gear tractor, you can usually bump a little more transient torque by popping the clutch. Limiting factor is spinning, breaking an axle or gear component, smoking the clutch or stalling. Nice to know the relief will regulate the max torque.

Note to remember, I think you'll find you can cook the fluid in your hst in short order if you continuously cause the relief to operate. Almost the power the engine is developing is being disipated in the fluid at relief valve.
Ken

( I thought more foot pressure meant more HP. When in actuality a lighter foot pressure will deliver the most HP to the wheels. I hope some of this has helped you a bit. )

SacandagaBrad · Feb 12, 2004

Re: How much \"slip\" on your TC hydrostatic?

( When in actuality a lighter foot pressure will deliver the most HP to the wheels. )

Maybe I'm not giving it a chance. Is there a lag time where it takes a second or two to kick in? I always try light pressure first, and when nothing happens I push down more on the pedal immediately for lack results, knowing that I am in effect putting it in higher gear. 95% of the time that machine has more power than I need, I'm sure I'm doing something wrong.

I'll have to run some tests this weekend. It'll take time, but I'm sure my wife will understand the importance of the research /forums/images/graemlins/wink.gif

Thanks for the input.

Brad