No movement when stuck in 4wd

[fatjay]

When I run 2wd and my blade catches on something, my back tires spin. However when I run 4wd and my blade catches on something, they don't. The tractor can't overcome the traction, it makes sense. However, it doesn't bog the engine at all, I just push down on the pedal and it doesn't move. I don't want to break anything so I didn't push it.

Is this normal opperation for a HST?

 

[Mike.O]

I've heard pressing the HST pedal referred to as equivalent to shifting gears up, therefore pressing the pedal further negates powering through it. You wouldn't want to upshift a gear tractor to power through things, I believe pressing the HST pedal all the way down is the same principal. I believe the best thing is to firmly but consistently press the HST pedal just a little bit for the best power.

I'm not sure if I described that best. I'm sure someone can give you a more technical description.

 

[RCW]

Jay - Are you in High or Low range?

Your HST pedal isn't like your gas pedal on a car/truck.

More pedal doesn't equate to more power - in fact less HST pedal and more RPM can be better in a tough spot.

It doesn't sound abnormal to me, unless I'm missing something!

Whoops....Mike types faster than I do!

 

[nickelplated5s]

Like RCW said; shift down rev up.

 

[fatjay]

When using the blade I'm usually in low or mid range. When pressing the pedal, even a little bit, if the wheels aren't moving at all, that just seems like it's slipping somewhere, or would bog the engine? The less pedal more power thing makes sense, though.

 

[conropl]

When using the blade I'm usually in low or mid range. When pressing the pedal, even a little bit, if the wheels aren't moving at all, that just seems like it's slipping somewhere, or would bog the engine? The less pedal more power thing makes sense, though.

I think I'm with you on this one. It sounds like in 2WD you are traction limited and your tires spin, but in 4WD you are power limited because you cannot create enough power to the tires to get them to spin (when the tractor is up against an immovable object - pushing on a large tree - for example). With my tractor, if the tires are not spinning and the tractor is stationary, then the engine is going to bog down as I push the HST peddle down. I agree this would be more pronounced in Med or Low ranges, but you are not talking about high range in your description. With mine, I have a "Stall Guard" feature that would kick-in to prevent stalling, but I do not think your tractor has that feature.

I am not the expert here, but I would think that if you are not moving, your tires are not spinning, and you have sufficient RPM's to feed enough flow/pressure to the HST; then I would think something is wrong, and there is slippage somewhere else in the system.

Just doesn't make sense to me, and that is not how mine seems to operate.

 

[Bulldog]

I remember my brother looking at a NH tractor once. He tried to drive over a 4" curb and going straight on it wouldn't do it. HST looses so much pulling power because it's not direct drive (so to speak) like a gear trans. I guess they have their place but to me it's better suited for a lawn mower instead of a tractor.

I run into situations all the time where I need all the power I can get in deep mud putting hay out. If it didn't pull I'd be getting pulled on a regular basis.

 

[BAP]

I remember my brother looking at a NH tractor once. He tried to drive over a 4" curb and going straight on it wouldn't do it. HST looses so much pulling power because it's not direct drive (so to speak) like a gear trans. I guess they have their place but to me it's better suited for a lawn mower instead of a tractor.

I run into situations all the time where I need all the power I can get in deep mud putting hay out. If it didn't pull I'd be getting pulled on a regular basis.

Actually, it’s not true that HST machines loose lots of pulling power. Most large machines like Combines, Self Propelled Choppers, Buldozers, Excavators, Payloaders and Many Large Tractors use HST a will pull like there is no tomorrow. They can actually go better because you can control the speed much better so you are at maximum torque at the wheels without just spinning the wheels like crazy. I have run many of the machines listed above and I will take a properly set HST over a gear drive any day. Sounds like the OP either had it in the wrong range or something is slipping somewheres.

 

[al m]

I suspect the clutch or the hst is the issue

 

[Bulldog]

I know NH said their hydro lost about 40% pulling power compared to a gear trans. No HST that I've ever been on is as strong as a gear trans.

I'll agree about the speed control which can be nice but I'm not impressed with HST in general. I've been on all the equipment you mentioned except for a chopper. HST dozers or loaders don't even come close to having the power of one with a powershift transmission.

Just my opinion of course but I'll never be on the HST bandwagon.

 

[sheepfarmer]

To complicate matters, there are HSTs and HSTs. I wanted a geared tractor (coming from a Ford 8n I thought that was how a tractor should be), but the dealer talked me out of it. The L3560 solenoid controlled hst doesn't exhibit the slow down phenomenon described above. However the B2650 transmission, besides being noisier and jerkier, does. It will get the job done but requires the operator to pay attention to rpm.