CK35HST trans operation

[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.