What is the phenomenon called...

[BAP]

Could be the hydraulic oil is low. Should not operate on a steep hill in 2 wheel drive.

 

[CobyRupert]

Low range
Fairly steep 20%+
Running at 3000 rpms
Pedal fully depressed
In 2wd (used 4wd but on dry asphalt don稚 like to do this)
No sound difference
I stopped it by quickly moving 4wd drive lever into 4wd
Back into control after doing this.
Task was pushing my trailer up my driveway to work on aluminum ice fishing shack (on the trailer) near my garage. Ice shack weighs about 400 lbs and trailer is a dual wheel 16 ft flatbed

How could it be the hydrostat being overcome if putting the tractor in 4wd "fixes the problem". That does not compute. The hydro is the hydro. 2wd or 4wd makes no difference. All I can go on is my own experiences. I say there is a problem with traction of the tires to the ground. How about having a 2nd observer standing beside the tractor to see what he/she can see? I have also heard of wheels slipping inside of the tire bead too.

Good point that there is the (slight?) possibility of tire slipping in bead. But note OP say the "pedal is fully depressed", when he should of let up on pedal to go uphill. HST may of just been overwhelmed. But this may not explain "freewheeling" forward downhill.

 

[bcp]

But note OP say the "pedal is fully depressed", when he should of let up on pedal to go uphill.

Not saying the OP did this, but some forget, under stress, especially, that the pedal is not like a car gas pedal. It is more like the gear shift.

Bruce

 

[Mowbizz]

Basically my BX is pushing its limits by trying to move this trailer uphill, I know this. Just wondering why all of a sudden the hydro just gives up in 2wd but goes up fine in 4wd. Has something to do with 2wd vs 4wd.?

 

[4570Man]

I think either the HST is screwed up bad, or you're missing what's actually going on. 2wd or 4wd makes no difference in the transmission itself. The transmission shouldn't freewheel in low range.

 

[Luke'sScreenName]

Could it be slipping out of gear at the 4wd transfer case? Into neutral?

 

[Texas Fella]

I would say stop pressing all the way down on the pedal. When the pedal is all the way down, you are "asking" the HST to give you speed, not torque. When you press only part way down, you "ask" the HST to give torque, not speed. A little oversimplified, but basically true.

I suspect that the HST is going over relief (to much load) when going up the hill. Then the operator stops and shifts to 4wd (which will help a little) and then re-engaged the HST (begins pressing the pedal). Since the pedal is not all the way down (beginning to be depressed) you get more torque out of the HST. That combined with the 4WD could allow you to climb the hill. This is all speculation since I have not seen it happen.

I would say keep your RPM's up, only engage the HST pedal 1/2 way, low gear and 4wd. If that does not work, you are doing too much. Just my two cents.

 

[Mowbizz]

This is not something I do regularly mind you it was just for convenience and being next to the work area while we were installing foam board insulation in the ice shack.
I think the suggestion of only depressing the pedal slightly, enough to go forward, is a good one! This makes sense to me that I知 asking too much of the HST by pushing the pedal all the way.
I wont be doing this anytime soon anymore if at all...
The ice shack work is complete and from now on there is no need to bring it up the hill!
Thanks all for the suggestions theories and insults!

 

[dodge man]

To the OP, I don't know if you picked up on this, but it is possible that the rim is slipping inside the tire. Someone else mentioned this and I've had it happen to me. Its hard to pick up on unless you lean out and look at the wheel.

 

[Mowbizz]

Yes...thinking about this too! Sounds quite impossible but stranger things have happened!