OK - the hydraulic fluid also runs the transmission. Use white
hydraulic oil -universal hydraulic and transmission fluid - from your
farm equipment supplier or farm/industrial lubricant dealer. DO NOT
SUBSTITUTE. Transmission and hydraulic pump and valve repairs are NOT
CHEAP - and the fluid is NOT terribly expensive. Good engine oil is
more expensive. So is automatic transmission fluid.
Tractor hydraulics may be very carefree, or not depending on what the
hydraulic fluid is doing. Universal Tractor Fluid (UTF) covers most
specs at a (adjusted for the price of everything oily going sky-high)
reasonable price - but some tractors that are not using it in the
transmission can get away with a more boring fluid in the
non-transmission hydrualics. Pushing cylinders in and out is less
demanding than transmission work.
OTOH, UTF works just fine in boring hydraulics too, and means only one
fluid to not get confused about which goes where. It usually does not
cost that much more than a more boring fluid, unless you are buying New
Holland or John Deere or whatever name-brand overpriced fluid rather
than a generic that meets the same specs. Do make sure that any generic
you buy meets the specs your equipment calls for, if you didn't build
the equipment yourself.
For homebuilds, UTF or ATF or Power Steering Fluid are typical safe
choices. If you just need to refill a jack, most anything oily works,
but not for long if you don't fix the leak (since you should not have to
refill a jack unless you drained it and tore it down.)
And even then it better stay sealed. The moisture that does get in likes
to settle into the low spots and cause rust.
Seen that happen a lot when the stuff first started being a fad item
with the rod set.
And there are thick hydraulic oils for lower pressure
applications like most tractor/farm equipment hydraulics, and thinner
ones for high pressure (the 10,000 PSI pumps and cylinders used by
Enerpac and others.) My hydraulic crimpers (made by AMP for larger wire
sizes -- up to 4/0 -- have (as one option) an electric pump, and that
would be quite unhappy with the thick tractor/farm fluid. For that, I
wanted to get the Enerpac fluid. As alternatives to that (which has a
limit switch at 8600 PSI IIRC), there is a foot pumped one also from AMP
(stops building pressure at about the same setting), and I can also use
an Enerpac hand pump (which will go all the way to 10,000 PSI) -- it all
depends on how many terminals you want to crimp -- and in how confined a
For that matter -- so will water (where the name "hydraulics"
came from, after all. :-) But not for long with most things which are
likely to rust. If you want to use water, you want the pumps and
cylinders constructed of materials which won't rust or otherwise corrode
as a result of being in constant contact with water.
By you -- or by others hired to operate it? :-)
"DoN. Nichols" fired this volley in
By me, the terrain, the Florida summer temps, and my son. I only mow my
own lawn now, but kept the mower.
It's the nature of these big commercial ZTRs to go FAST. Mow fast,
reverse directions fast, turn fast, stop fast. It's a two-stick control,
like a tank. It's a 20-acre/day mower.
Because of the way it's rigged, it's possible to slam it in reverse from
full speed. Of course, one understands that with hydraulics that just
means a very fast deceleration from full to zero, followed by a fast
acceleration to full reverse. These are variable-displacement (swash-
plate style) pumps; one for left drive and one for right. The rate
changes are fast enough that you can hear snubbers unseating, and
occasionally will hear the pump belt slip.
It's run like this for 19 years. The only expensive part to replace so
far has been the blade clutch. It was a cheezy Bendix Electric part that
was not repairable (not meant to be). It lasted eight years, then we
switched to an Ogura repairable clutch, and haven't even needed to
replace the wear plates yet.
But it gets expensive if something does go wrong. New traction pumps are
about $600 each (two), and the traction motors - which _also_ are the
rear wheel axles - are about $800 each.
I used to spend - on average - about as much keeping it in good condition
as I would per year just on the mortgage for one of those big-box store
beer-can mowers. We got about 3 years out of a 'conventional' rider
before it was too far gone to repair economically. Anything Murray or
MTD has had its hands in is destined to fail early and often.
Now, I generally only replace belts, filters, oils, and one set of blades
a year. Something pricey will fail, though... has to!
The point of ALL that was simply that 20W-50 motor oil has held up well
for 19 years in an abused hydraulic system that is always running hot.
I've _never_ in 60+ years seen a tractor manufacturer spec anything as
heavy as an equivalent to SAE 90.
Link to the Deere take...note that there is no single industry
equivalent standard/spec for transmission/hydraulic oils so each
manufacturer has a set of minimum standards of their own. They're all
similar, of course...I don't think any modern vendors are using engine
oils as their recommendations though other than perhaps the
homeowner-class small machines, perhaps for end-user convenience might.
Not to say you might not and probably can "get by", but as others have
noted, there's little to be gained by trying to cut corners and
potentially much to lose...we buy/use HyGard by the 55-gal drum and
Plus-II engine oil in bulk 250-gal delivery for the tractors since it's
qualified for the extended change interval it's well worth it (since
even the "small" old 4440 takes 18-qt/change, extending from 100 hr to
500 is a big improvement.
If you've got old stuff w/ no warranty concerns, just use a good quality
generically branded and you'll be fine if it's of the proper viscosity
and wear rating for the application. W/ a $200k tractor, it pays to be
in compliance w/ manufacturer's warranty spec's whether they're
recommendations are any better than anybody else's or not. :)
I have a little Poulan Yard Tractor (Glorified Lawnmower) with the
slightly heavier trans-axle. From the HydroGear Manual:
The fluids used in Hydro-Gear=AE products have been carefully selected,
and only equivalent, or better products should be substituted.
Typically, an engine oil with a minimum rating of 9 cSt (55 SUS) at
230=B0 F (110=B0 C) and an API classification of SJ/CD is recommended. A
20W-50 engine oil has been selected for use by the factory and is
recommended for normal operating temperatures.
Fluid Description Volume
20W-50 engine oil 0.95 gal. (121.6 oz) (3.59 liters)
I know you were mainly disputing the 90wt recommendation but thought
you might find what they are putting in the hydrostatic mower trannies
Grand Rapids MI/Zone 5b
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And to confuse things even more, for some reason I don't understand,
gear oils and engine oils use a different SAE viscosity scale. The
viscosity of SAE 90 gear oil is equivalent to SAE 40 or 50 engine oil.
David Lesher fired this volley in news:jt2nej$t72$2
(what's the sound of the buzzer?)... I owned an 8N (1950) for twelve
years. Ford changed the gear case/hydraulic recommended oil on that
machine in (about) 1995 to a 30W GEAR oil, which equates to about 15W
I switched to the new oil at the time of a paint job, and the only thing
I had to do to accommodate the lower viscosity was to change the o-rings
on the lift cylinder (which on an 8N is only about a half-hour job).
Acutally I specifically mentioned I could believe that for the
application...you won't find it recommended for one of these, though...
BTW, it's not as green outside here nor are ours this shiny any more...