CK35HST trans operation

[gtrippleb]

Would someone be able to inform me on how the hydrastatic trans works on a ck35hst? I test drove one the other day and I had to press a clutch in before moving the lever to the range I wanted. I thought to myself, why would I need to push a clutch in to put a hydrostatic transmission into range as I don't do this on my lawnmower, sc2400, or my t2320. I didn't have time to talk with the salesman as I was on my lunch break so I thought I would ask.

Thanks

 

[k0ua]

Would someone be able to inform me on how the hydrastatic trans works on a ck35hst? I test drove one the other day and I had to press a clutch in before moving the lever to the range I wanted. I thought to myself, why would I need to push a clutch in to put a hydrostatic transmission into range as I don't do this on my lawnmower, sc2400, or my t2320. I didn't have time to talk with the salesman as I was on my lunch break so I thought I would ask.

Thanks

Keep in mind that the range selector is just a 3 speed gear transmission after the hydro-static transmission in the driveline. Sometime gears do not always align tooth to tooth. Sometimes a small amount of movement of the input shaft and gears on it can make the alignment "line up". you can just gently touch the hydro pedal just a smidgen to sometime get this to align.

You don't actually have to push the clutch in. At least you don't on most units. But you need to be stopped, but sometimes letting the tractor "drift" just a tiny amount will allow the range selector to mesh the gears and get in the range you desire. Keep in mind that as the gears wear just a bit, their edges will be a little less sharp, and changing ranges will get a little "slicker".

On my last tractor which although it was a Kubota L3400hst, is similar to the Ck35, I used to always push the clutch in to change ranges, until I realized it was not necessary. On my current Kioti tractor a DK35se, there is no clutch to push in. It simply doesn't have one. But you still need to be stopped or sometimes you have to drift just a bit to get it to mesh. Usually you don't, and rarely now that is has some hours on it.

 

[gtrippleb]

James,

Thanks for the information. I really didn't think about how the three ranges were tied into the transmission. Both of my tractors are two ranges with the T2320 having a neutral between one and two and the Sc2400 just has high and low without a neutral position with neither having a clutch. On the T2320 sometimes I have to play with the forward or reverse pedals to get it to change from a range to neutral.

I just started looking for something around 35hp and was looking at the ck35hst so I thought I would ask about the transmission and why it had a clutch.

 

[k0ua]

The reason for clutches on some Hydro tractors is mostly to engage the PTO. Of course many have safety start switches tied to the clutch pedal also. Also the hydro needs to be in either neutral or a clutch pushed in to disengage they hydro pump to take that load off of the starter spinning up the engine. But you have to and have a way to engage the PTO. Some do it with electrical activated hydraulic valving, and others do it with a clutch.

 

[TJP89]

Keep in mind that the range selector is just a 3 speed gear transmission after the hydro-static transmission in the driveline. Sometime gears do not always align tooth to tooth. Sometimes a small amount of movement of the input shaft and gears on it can make the alignment "line up". you can just gently touch the hydro pedal just a smidgen to sometime get this to align.

You don't actually have to push the clutch in. At least you don't on most units. But you need to be stopped, but sometimes letting the tractor "drift" just a tiny amount will allow the range selector to mesh the gears and get in the range you desire. Keep in mind that as the gears wear just a bit, their edges will be a little less sharp, and changing ranges will get a little "slicker".

On my last tractor which although it was a Kubota L3400hst, is similar to the Ck35, I used to always push the clutch in to change ranges, until I realized it was not necessary. On my current Kioti tractor a DK35se, there is no clutch to push in. It simply doesn't have one. But you still need to be stopped or sometimes you have to drift just a bit to get it to mesh. Usually you don't, and rarely now that is has some hours on it.

k0ua, I think you may be incorrect here. One of the few things the manual states clearly is that the clutch must be pressed in to shift ranges. I once forgot to clutch and tried to shift, and the grinding noise that ensued immediately reminded me that shifting is necessary. I wouldn't be surprised if the manual was incorrect on this point, but it seems that pushing the clutch is necessary on the CK series. Maybe someone with more hours on their CK could clarify here.

 

[TJP89]

Keep in mind that the range selector is just a 3 speed gear transmission after the hydro-static transmission in the driveline. Sometime gears do not always align tooth to tooth. Sometimes a small amount of movement of the input shaft and gears on it can make the alignment "line up". you can just gently touch the hydro pedal just a smidgen to sometime get this to align.

You don't actually have to push the clutch in. At least you don't on most units. But you need to be stopped, but sometimes letting the tractor "drift" just a tiny amount will allow the range selector to mesh the gears and get in the range you desire. Keep in mind that as the gears wear just a bit, their edges will be a little less sharp, and changing ranges will get a little "slicker".

On my last tractor which although it was a Kubota L3400hst, is similar to the Ck35, I used to always push the clutch in to change ranges, until I realized it was not necessary. On my current Kioti tractor a DK35se, there is no clutch to push in. It simply doesn't have one. But you still need to be stopped or sometimes you have to drift just a bit to get it to mesh. Usually you don't, and rarely now that is has some hours on it.

k0ua, I think you may be incorrect here. One of the few things the manual states clearly is that the clutch must be pressed in to shift ranges. I once forgot to clutch and tried to shift, and the grinding noise that ensued immediately reminded me that shifting is necessary. I wouldn't be surprised if the manual was incorrect on this point, but it seems that pushing the clutch is necessary on the CK series. Maybe someone with more hours on their CK could clarify here.

 

[k0ua]

k0ua, I think you may be incorrect here. One of the few things the manual states clearly is that the clutch must be pressed in to shift ranges. I once forgot to clutch and tried to shift, and the grinding noise that ensued immediately reminded me that shifting is necessary. I wouldn't be surprised if the manual was incorrect on this point, but it seems that pushing the clutch is necessary on the CK series. Maybe someone with more hours on their CK could clarify here.

Well that is possible. I was going by my previous HST tractor with a clutch, which was a Kubota. You do not have to clutch with it. It does no harm, but you can change ranges without clutching as long as the hydro pedal is centered and the tractor is not moving. Again you may have to let the tractor "drift" or roll slightly to get the gears to mesh. I have no experience with the CK series, but assumed it would work as the previous Kubota. As my DK does not have a clutch, and you can change ranges as I noted above.

 

[Scrambler82]

Too bad they weren't all like the SC2450.
Hit the pile in high, no problem just grab the hi/low select lever and pull it in low as you approach the heavy stuff, that easy.

I guess Yanmar had a great idea there.

I have only used the SC2450 and found the HST to be a great tool when moving stone, snow or dirt.
I am thinking on another tractor, I will have to make sure to ask about the HST/Clutch thing before buying for sure.

 

[k0ua]

Kubota has their HST+ on the Grand L models, that is the cats meow. with their hi/lo in the same range you can usually stay in MED range , for most loader work, and shift on the fly with their hi/lo lever and get the "grunt" you need for pushing and still have the speed you need for transport without ever changing ranges. In effect you have 6 ranges, 3 actual gear ranges but multiplied by the hi/lo in each range. This of course is not available in their "standard" hydro tractors, but is on their "deluxe" tractors the Grand L series. HST+ has many other features as well.

 

[TJP89]

Kubota has their HST+ on the Grand L models, that is the cats meow. with their hi/lo in the same range you can usually stay in MED range , for most loader work, and shift on the fly with their hi/lo lever and get the "grunt" you need for pushing and still have the speed you need for transport without ever changing ranges. In effect you have 6 ranges, 3 actual gear ranges but multiplied by the hi/lo in each range. This of course is not available in their "standard" hydro tractors, but is on their "deluxe" tractors the Grand L series. HST+ has many other features as well.

Yes, The GL60 series has, in my opinion, the best hydrostatic transmission on the market. The HI/LO lever by itself makes it that, everything else is extra. If it wasn't for the price, the GL3560 would have made me a Kubota guy. Now, if only Kioti would actually steal Kubota's HST+ and put it in a DK...

 

[dfkrug]

Also the hydro needs to be in either neutral or a clutch pushed in to disengage they hydro
pump to take that load off of the starter spinning up the engine.

As long as your GO pedal is in the center position, the HST pump does not significantly load the engine or starter
motor. Indeed, I disabled the clutch pedal interlock so I can start my CK30 in gear and without depressing the
clutch. It is only unsafe to do that if you try to start while depressing the pedal.

All my HST tractors had balky range shifts, so I used the foot clutch if it had one. Some do not, like your HST-SE,
or my Deeres. Pressing the clutch pedal is not truly necessary, but if it helps to unload the gears, then it makes
sense to do it.

 

[TJP89]

As long as your GO pedal is in the center position, the HST pump does not significantly load the engine or starter
motor. Indeed, I disabled the clutch pedal interlock so I can start my CK30 in gear and without depressing the
clutch. It is only unsafe to do that if you try to start while depressing the pedal.

All my HST tractors had balky range shifts, so I used the foot clutch if it had one. Some do not, like your HST-SE,
or my Deeres. Pressing the clutch pedal is not truly necessary, but if it helps to unload the gears, then it makes
sense to do it.

OK, interesting. The clutch is only used for unloading the gears and is not actually disengaging the driveline from the transmission as in a manual. So I can shift without clutching as long as the tractor is stationary and the pedal centered? I learn something new every day So now I have a question. Often I put the CK in N and it does not require moving the HST pedal to do so. But then, when I want to shift into gear, not having moved anything, I have to jiggle the HST pedal. It seems if the gears were lined up when I shifted out of gear, they should be lined up when I want to shift back in to gear if nothing has moved. It confuses me, please explain.

 

[k0ua]

I would imagine that the gears move a tiny amount as soon as you come out of neutral so they are not lined up by default any more.

 

[davrow]

I have the CK27HST, basically the same as the CK35HST. The clutch pedal must be pressed to start the tractor. My belief is so you don't start the tractor with the PTO live. But that is a safety switch, not a physical requirement.

I have never used the clutch at any other time. It is definitely not needed when shifting on an HST tranny. Gear is, of course, a different story.

Yes, I 'rock' the tractor when shifting is troublesome. Going from neutral to 2nd is almost always easier than neutral to 1st. I usually turn the tractor off in the neutral between Low and Medium, I don't use High much.

 

[oldpilgrim]

I don't need to press the clutch on my Mahindra 3016 HST but it shifts much easier if I do. It can be VERY hard to shift if I don't.

 

[dfkrug]

The clutch is only used for unloading the gears and is not actually disengaging the driveline
from the transmission as in a manual. So I can shift without clutching as long as the tractor is stationary and the
pedal centered?

The clutch does disconnect the HST from the engine, and the PTO, too. If the HST swash plate is perfectly
centered, then it should not be trying to turn the gearbox, even with the engine on and clutch engaged. But don't
forget that the gears can be under pressure from unlevel ground, too.

 

[dfkrug]

The clutch is only used for unloading the gears and is not actually disengaging the driveline
from the transmission as in a manual. So I can shift without clutching as long as the tractor is stationary and the
pedal centered?

The clutch does disconnect the HST from the engine, and the PTO, too. If the HST swash plate is perfectly
centered, then it should not be trying to turn the gearbox, even with the engine on and clutch engaged. But don't
forget that the gears can be under pressure from unlevel ground, too.

 

[TJP89]

OK, I think I get it now. As I have stop completely to shift anyway, might as well put in the clutch too, can't hurt. I had a decent understanding of the HST before, but its better now. Thanks for the education!

 

[dfkrug]

Also note that ANYTHING that puts pressure between the gear teeth makes it harder to shift
ranges. This pressure can come from the HST, and external forces on the wheels, but also the
brakes and any internal gear/shaft/bearing/fork friction. Not obvious is the friction caused by
the 4WD mech, even when the 4WD shift fork is disengaged. Push-pull forces have to be
balanced amostly perfectly for the gears to be loose.

I find that range shifting is easier when you lift the front wheels off the ground with the loader,
whether or not the 4WD is engaged.

Cold vs hot oil makes a diff, too. I once owned a car that, despite having synchros, did not like
going into first gear until the oil was warm.