CK20H tranny pop off seems weak

[getut]

Ok.. I got my new CK20HST last night and got about 2 hours play err seat time on it. Actually got a little bit done while I was learning it also but I have a question for anyone else out there with the HST model of CK20.

It seems that the hydraulic pop off for the HST tranny is set too weak. On flat North Carolina grass covered red clay, my new CK20 will just barely pull hard enough to VERY slowly slip the back wheels in 2 wheel drive (If I measured it, I'd say it would run out of fuel before 1 RPM) and not even close to slipping tires in 4 wheel drive.

Now.. for more information for you other guys to compare against. Like I said, I am in NC and it was grass covered red clay. I was pushing the FEL against a fallen cedar tree trying to finish it off. I had the rotary cutter on the rear, but no loaded tires or anything.

Is this about normal for you other owners of this model? Could the rotary cutter alone be making it bite this good or does it sound like something is set too weakly on my machine? I was tached up to about 2200 RPM (new machine and didn't want to push any further yet) and was just barely pushing on the HST pedal in low range for the example above.

Oh.. and by the way... getting some pics taken.. I'll start a thread for you picture junkies tomorrow once I stop worrying that something is wrong hehehe.

 

[KiotiJohn]

</font><font color="blue" class="small">( It seems that the hydraulic pop off for the HST tranny is set too weak. On flat North Carolina grass covered red clay, my new CK20 will just barely pull hard enough to VERY slowly slip the back wheels in 2 wheel drive (If I measured it, I'd say it would run out of fuel before 1 RPM) and not even close to slipping tires in 4 wheel drive. )</font>
This is not really clear to me. You say the hydro "pop off" is set too weak, yet you also say the tires slip. If the tire is slipping, turning, the hydro has not "popped" off, the tractor is trying to move. Maybe I just don't get what you're asking. When my tractor starts slipping, the tire turns pretty good, and I use the rear differential lock to get going again. Sorry if I'm missing what it is you expect. Help me out. John

 

[getut]

I guess pop is the wrong terminology. It IS <<trying>> to spin the tires but isn't getting anywhere. The engine is very slightly grunting, but no where near stalling yet the HST is not spinning the tires.

I know HST is not like a gear transmission, but I was expecting (notice the terminology... expecting versus knowing) that in low range especially, that the HST should engage and not slip to the point of bogging down the engine.

What I am seeing in reality is that even in low range, the engine has power left to give but the HST just won't pull hard enough to cause the tires to slip (well just barely when in 2 wheel drive, but not even close in 4 wheel drive in the situations listed in the first post).

Edit and clarification: I CAN cause the engine to bog if I push the HST pedal all the way down, but when slighly depressed which should be the strongest pull, then engine never bogs that much, but the tires dont spin.

 

[cag]

From what I read here GETUT your CK20 did not have the torque you thought it had. I think I know what your trying to explain. How about this example; Your using your FEL to move a pile of dirt as you it the pile with FEL you would expect the tractor to work for you by digging in or tire spinning or engine bogging down which at that time you would drop to a lower gear. But none of the above is happening or barely happening .... I'm no expert but I would expect the CK20 to show some kind of willingness to go forward into the pile . And it's not. /forums/images/graemlins/frown.gif

 

[To20Chris]

If the engine is not bogging a lot or stalling, then it is not a power issue. It sounds like the power is not making it from the engine to the wheels. Does this only happen when the HST pedal is just of the center? There will always be some losses in the HST system - at some point as you are just tipping into the pedal and the pump is just beginning to move fluid, most of that will be wasted and not result in much movement on the output. Once you overcome that loss, then it will feel much more linear. If there is something wrong that results in more fluid pumping loss, then of course it will be much more noticeable.

So I think that the assumtion that just off center for the pedal is equivalent to a really low gear may be faulty. The HST system is similar to a really wide variable ratio transmission, but it is not an infinite range.

The guys who actually use CK20HSTs should be able to help you figure out how far you need to move the pedal to get efficient power transfer.

 

[KiotiJohn]

I think I would have to try the tractor myself to see what problem you're having. My CK will turn the tires when I get into the right situation and I engage the rear differential lock to get it moving. If you can't turn those tires in the right situations, there may be something wrong. Have you insured that the hydro level is between the marks on the dipstick? They should not be higher or lower than the two marks on the stick. I'm not really sure why spinning tires is something you're looking for, and I don't think it's a productive situation to be in, but even when they do "spin" it's not something that's like a car or truck turning wheels very rapidly. They break loose and turn at a relatively slow pace based on the amount of HST pedal you're giving, but never really FAST.
I think the question is, are you getting the work done you need to get done? Is the relief valve releasing the pressure when it shouldn't? Are getting into overload situation and being unable to get your work done? If so, then there probably is a problem. I hope you find there is no problem, keep us posted. John

 

[getut]

I get what all of you are saying. I'm by no means expecting it to smoke tires but was really expecting one of a couple outcomes depending on available traction.

1) Pull to the point of choking down the engine if traction is good enough.
2) If engine ISN'T choking down and I'm not moving forward then tires would be spinning.
3) If neither of the above happens then hydraulic pump is probably overloading and is the limiting factor.

Like I said.. Right after I got the machineI was just pushing on a cedar root ball with the FEL. If I started and slowly started pusing the HST pedal, it would progress from a slight whine when only very slightly pushed, through a very strong whine when depressed about an inch, to slightly less of a whine with the engine starting to lug when the pedal was almost all the way down and the tires never spun through any of this.

More info from last night. I did take the rotary cutter off the back and purposly put it in a few situations where it couldn't possibly move forward again. This time it would spin the tires in the same situation. It just appears that the extra weight of the rotary cutter increased the traction beyond the limits of the HST and it appears that the weaker of the 2 links is the HST not the available engine power. So I guess I am actually bumping into option 3 above rather than either option 1 or 2 as I was expecting.

Don't get me wrong it pulls really hard but NOT to the point of using all availble engine power (and choking down the engine). There always has to be a weak link, I was simply expecting it to be somewhere different.

I got some more seat time last night, had a good time and got alot done while I was doing it. I AM very satisfied with the tractor but was a lilttle perplexed at first with the unexpected behavior.

 

[cag]

Getut I don't own a kioti or any tractor . I driven loader and backhoes in the past. I found your situation to be of interest I would expect the CK20 to show some sort of willingness. I might be reading this wrong but I get the impression the CK20HST as no guts. I don't want to insult any one by this statement as some of you know I'm interested in the CK20HST CAG

 

[getut]

Don't get me wrong it pulls (or pushes) really hard. I was just assuming , since I've never owned or driven an HST tractor before, that the engine would bog down if the traction were there. That isn't the case, the HST slips first. I've already pulled a 60" box scrape through red NC clay and it does fine and actually does pull to the point of slipping the tires. But when it was loaded down with the 60" rotary cutter and got its fill of traction, the HST slipped before the engine bogged down.

 

[depratt_equip]

It sounds like you have the traction there so the wheels should not be spinning. The engine should not really bog down either. If the HST gets in position where it does not have enough tractor power to perform the task (too small of tractor for job) it will pop the relief valve. In a way it’s kind of like the tractor saying "hey this is too much for me to do, I’m not big enough". Your situation just sounds normal of HST transmission in general. If it was a gear I would expect the engine to bog down and die, but because of the relief valve in the HST it will perform different.

I had a Kubota HST in the other day (B20) 20HP Tractor and was playing with it, when I went to load it on the trailer I had to put it in 4wheel drive to get it up the ramps (just a normal 16ft trailer 4ft ramps) it was bogging down the HST and would not move no matter what position the pedal was in. Wheels would not spin at all. The only times I would expect the HST’s to spin a tire would be in slick situations (mud, snow, wet wet grass). If you have traction and pushing against a solid object and a heavy one and the tractor is not big enough to over come the object I have found that it will pop the relief valve, and in turn not spin the tires.