2520 transmission question

hizoot · Feb 19, 2011

My 2520 has 23 hours on it. (2 months old) Last night, after idling around for a bit, I decided to "blow it out" some before putting it up for the evening.There is a fairly steep and long paved hill that runs in front of my home. The revs were around 1500 rpm, high range when I took off. About half way up the hill I decided to open the throttle quite abit more for more speed ( I had the foot pedal pinned forward already)...well, the engine didnt increase in revs after applying more throttle, nor did I gain any ground speed. I let off about half on the foot pedal and the engine revved immediately to about 2500 rpms. is this normal...or do I have a problem i need checked out? It sure doesnt seem normal...

Runner · Feb 19, 2011

I think it is normal.

On a hydrostatic transmission, having the "pedal to the floor" is like having your car in top gear. If you're going along up a hill in high gear (manual transmission) and don't down shift, even if you push the gas all the way to the floor, you may not accellerate if you're going up a steep enough hill.

I believe you experienced the same thing with your 2520. When you let off the pedal, it was like downshifting, which explains the increase in RPM's.

I see that condition all the time when I'm mowing. I have some steep hills to mow and when I'm pulling my heavy rear mower up the hills in heavy grass, I have to let off the "go" pedal a little to keep the RPM's up enough to get over the hill... and that is in low gear.

AKfish · Feb 19, 2011

That's eHydro... if you want "power" you always have to let off the pedal.

You ever notice how easy it is to "bog" your tractor down by pushing too far on the pedal when you're in heavy grass or pushing the bucket into a pile of dirt?

It's just the opposite of an accelerator pedal. Always back off the pedal when the engine pulls down.

AKfish

kennyd · Feb 19, 2011

AKfish said:
That's eHydro... if you want "power" you always have to let off the pedal.

His machine does have the the "E" part of the hydro, but the theory is the same.

Think if the pedal as a variable gear, the more you push the higher the gear.

glc24 · Feb 19, 2011

Think if the pedal as a variable gear, the more you push the higher the gear.

I agree.
Put your front wheels against an obstacle, not more than a couple inches higher than the ground. In high range your machine won't budge,and the more pedal you give it, whatever measly pressure it had on that obstacle will diminish even further.

Greg

pdp11 · Feb 19, 2011

I would say that is not normal. I have a 2520 and I regularly take it for short trips on public roads. I run in high range with the pedal to the floor. I have never experienced what you described.

It seems odd that the engine RPM didn't increase when you opened the throttle. I can't imagine how the transmission would keep the engine from responding to the throttle.

Deadman · Feb 19, 2011

Mine does exactly like the original poster says. i play with it and see how it reacts to all kinds of different situations. Mine does just that, revs up after you take the load off of it. The pedal is actually applying more "work" to the engine, and the throttle is applying more "power/RPM". They are completely different. If you are going to give it alot of pedal, then you really should give it alot of throttle FIRST, so it has a chance.

pdp11 · Feb 19, 2011

I must never put enough load on mine to experience that. Even dragging the rear blade, I've never had the engine reduce in RPM to that degree. Although, if I'm headed out on the road in high range, I usually have the engine RPM up to 2500 first.

hizoot · Feb 20, 2011

Thanks guys...makes sense now. I guess with the load of the hill and full "pedal", it was at its full load at that rpm and wouldnt take any more revs. But I wasnt grasping that letting off the pedal would multiply the torque...kinda like gearing down. One of the minor reasons I chose a deere tractor is that I've owned a deere GT275 garden tractor since 94-95. I had never experienced that problem with it....but its gas,lower geared, and probably a little different technology. Thanks again!