I guess what I'm wondering is will the excess strain of this implement cause undo heat and strain on my hydrostatic unit causing damage to it.My little tractor has to last me several more years.If the box scraper will damage the unit I will borrow my sons J.D. to finish my scraping duties.Thanks for the awesome feedback folks
Scotty
Hi Scotty. I want to give you general considerations about the tranny, since your concern was about longevity.
You want to use it instead of the JD, but you don't want to hurt it. I will tell you things you already know, but having it grouped in one place may ease your mind. What I write below will be overkill for your question, but with summer coming on, and so many BX's on the board, maybe it will help someone.
In the following, the term "stall" means moving the foot treadle to go, but the tractor stops moving, or moves much slower than it should. I am not referring to the engine. When I talk about "heat", I am talking about heat generation the operator can influence, not all sources of heat.
What cools the tranny is the cooling fan, and heat radiating from the entire tranny casing. So, make sure the tranny is generally clean since dirt, film, dust, etc. can act as a thin insulating blanket, keeping heat in.
Periodically, it is a good idea to blow the tranny off with compressed air, and particularly, use strong blasts of air to the housing behind tranny cooling fan to get rid of the crud that seems to accumulate there over time. I try to keep all traces of oil off my tranny housing because grass and dust will collect there, and can become quite thick.
Keep the rpms high so the fan will deliver plenty of air to the pump/motor set. High rpms will not generate as much heat as it will liberate because the priority valve goes ahead and grabs it's share of the flow even at low rpms. Therefore we don't have to worry about the priority oil flow reliefs causing more heat at higher rpms per se so long as you don't turn your steering to the extreme left or right, therefore challenging the steering relief valve (and creating heat.)
The higher rpms will only increase flow to the lift and loader, which will dump the flow to tank without heating it much.
If you are using the lift or the loader, don't stall it at the end of stroke, or against loads (which will challenge the main relief, creating heat.)
What heats the tranny (beyond internal leakage) is any relief valve being challenged. The only reliefs you are possibly challenging with the box blade (if not the lift) are the reliefs for the hydro set immediately behind the fan.
If you are in low range, and your rpms are high, you are not likely to challenge them much. A good idea is to stall the tractor a time or two in the beginning to see which of the following are true: A) The wheels spin. B)the wheels do not spin.
If A) you have no real worries. You are not generating excessive heat with that setup. It is to be desired not to spin the wheels much though, because this is wasteful (wastes rubber, and does less useful work than could otherwise be accomplished if you kept things below the edge of spinning.)
If B)you will generate heat above normal each time you stall, so find a better/easier way. Just take it easier, and don't stall the wheels.
Your treadle determines how much oil the hydro set pumps(for a given rpm.) The relief pressure will determine how hard your wheels can pull. Stalling a tractor at a low foot treadle position generates less heat than stalling it at a high treadle position. The reason is:
flow x pressure = power. Pressure is set by the reliefs. This is presumed not to change. Flow is in proportion to treadle position. If we lock the wheels down, the power goes out the relief, and doing no honest work, it is transformed to heat. Low flow at a fixed pressure is less heat than high flow at that same pressure.
