Hydrostatic pedal pulsating

madisonhawk · Jun 21, 2015

Hi everyone,
I just bought my ck30 hst. about a month ago and have about 10 hrs. on it now. I noticed recently that when you first start up the tractor and are on level ground in med. and high range the pedal will pulsate a little when you move forward and backwards, but more so in high. After your done using the backhoe and or the loader for awhile and then try moving the tractor on the level in either range the pedal pulsates a lot worse, especially in high and the tractor responds to the pedal by a jerking motion moving in either direction. The pedal actually gets harder to push down and feels like there is pressure built up in the hydrostat and it's pushing back at you. I have driven other hydrostatic trans. and never experienced this before. I know there is a wealth of knowledge on this site and I thought I would ask all of you if you have any ideas what might be going on with my tractor before contacting my dealer about this? Another question I have is I noticed that sometimes when I try to change ranges I have to move the loader up or down to get the lever to move? I read some others had the same problem and did this to get it to shift ranges. Was wondering what may be the reason for that also? I appreciate any and all help in this matter.
Thank You

PS, Got the pictures taken of my ck30, but have to make them smaller to fit format.

tman1020 · Jun 22, 2015

I think the reason it's hard to shift ranges is the tractor can have resistance against the drive line at times. Like on a slight grade or when pushing into a pile. A very light tap on hydro pedal in opposite direction of resistance while shifting ranges usually solves the problem to relieve any resistance. Remember very light tap. I have also heard others mention pushing in the clutch helps. I believe that the reason moving the loader helps is that it is shifting the tractor slightly just from the momentum of moving the loader. I too have had some minor pulsating from time to time and have heard of several other people mention it. I am not sure what causes it I think its worse at lower RPMs. I will be interested to read other's posts regarding the pulsating also.

Coyote machine · Jun 22, 2015

I'm wondering if there is a way to disconnect the hydraulic fluid flow to the backhoe when you're not actively using it? On the DK series there is a lever to engage A or B rear remote(s). Is there something similar on the CK.
Tapping the hydro pedal is a way to get the range selector lever to move on the DKs too.

Note also that the HSTs do loosen up some with use, and 10 hours is nothing in the overall scheme of things. I would still bring your concerns to your selling dealer in case there turns out to be a 'real' problem with the HST function as you continue to put more hours on it.

Keep us posted as to outcome.

Notlaker · Jun 22, 2015

The Ck 30 does have the A B Lever with a Neutral in between to stop Flow. Should always be careful that this lever is in N with the backhoe disconnected.

bd53bz2 · Jun 22, 2015

Are you in 4wd or 2wd? 4wd on a hard surface will make the driveline bind and might give you feedback through the pedal.

k0ua · Jun 22, 2015

Pulsing in the pedal is usually caused by being in too high of a range and too low of RPM on the engine. Try it and see if when you have the pulsing, crank up the RPM and see what happens. Remember HI range is for ONLY transporting the tractor to move it down a flat road without heavy loading. LO and MED are for doing work, LO range is for doing heavy work at a lower speed, and MED is for doing lighter work at higher speed. Keep the RPM of the engine up to keep the flow rate of the hydrostatic pump up. The oil of any hydro thins out some after it gets hot. Tips for changing ranges have been covered by the above post's.

TJP89 · Jun 22, 2015

k0ua nailed it. Also, In HI, you will feel a lot of resistance against the pedal. Low rpms (under about 2000) will also do strange things. As noted, check your remotes, as that can mess things up too. Make sure there is no resistance on the driveline when shifting. The HST will take a few hours to loosen up.

madisonhawk · Jun 22, 2015

Thanks everyone for your input to my questions. Just to answer some of your questions, I have tried it at various rpms from idle to 2500 in med. and high in 2wd. with the A B lever in neutral on the flat after first starting the tractor and letting it warm up and the pedal pulsates just a little to near none and about the same wherever the rpms. are set. It's after I run the backhoe and or the loader for awhile and then try it the same as I did when first starting the tractor, that is when the pedal really pulsates in both ranges ,but especially in high. You could be right, maybe I need to get more hrs. on it as to get things broken in and loosened up. You are probably right Coyote Machine as to still contacting my dealer and talking to him about it.
Thanks again for all your help and hope you liked the pictures.

k0ua · Jun 24, 2015

Well, that is kind of a puzzler.. The only time in my DK35se, I get any pulsing is when the RPM's are real low, and the tractor is just "dogging" around barely moving.. Cranking up the RPM's a bit always fixes it.. I don't know what the problem could be.. best contact the dealer. I do believe that the pedal on a CK series is direct connect to the swash plate and does not have the hydraulic connection that the DK series has. Having never spend any time on a CK series, I can't really add much real world experience. I liked your pictures, they were very well composed.