To Hydro or not to Hydro??..What is the answer?

[eee]

I have never ever heard of a hydro " burning up".

John Deere puts the hydro's in there crawler dozers,450J,550J,650J plus other dozers as well.

 

[timb]

I would assume that true hydros used in heavier equipment (and not torque-converter set ups) have the cooling and fluid flow capacity to deal with the projected primary use of the machine.

A hydro in a CUT loses (let's not start the war over specific percentages again) significantly more power between the engine and the wheels than a gear tranny. That's not meant as a derogatory comment on hydros, it's just the nature of the beast. That power doesn't disappear down a black hole - it's turned into heat. Thousands of watts worth of heat. If the tranny cooling system isn't up to the job - then you're going to have major trouble. If I understand the process correctly - the heat is coming from fluid sheer inside the system. As the fluid heats up - sheer increases as the fluid properties change / break down. Can eventually be a run-away situation.

Unfortunately, I don't know of a single CUT that comes from the factory with even a simple tranny temp gauge. THAT would solve all this right quick. If whatever you're doing starts pushing the tranny into the iffy zone - you could back off, give it a rest, idle, whatever. You'd know the limits. Without that - you're just hoping your not crossing the temperature line where your fluid starts to deteriorate.

Of course the same is true of a gear tranny - without a good gauge you're only guessing you're still in the safe zone.

I guess you could say I like a well-instrumented machine. /forums/images/graemlins/wink.gif

FYI - I'm certainly not anti-hydro, it's a great system that is ideal for many CUT duties. But there are a couple of minuses as well that should be kept in mind. For most CUT owners and typical CUT uses, I honestly believe it's probably no contest. If your needs do happen to fall into the more extreme situations - I think it's helpful to weigh the pros and cons.

 

[eee]

I am not disputing what you say about temeprature etc. I am just saying I never have heard of a hydro burning up.Not to say they have never burnt up.
As far as extreme conditions I have had tested a lot of things on my tractor and the hydro and Yamnar engine have both performed flawlessly.

 

[PsRumors]

I have used my 4410 to pull a 5 shank all purpose plow and a 16" 2 bottom plow and have NEVER had a problem. The tractor never seemed to complain.

 

[eee]

I have skidded logs all day up these hills and hollows,logs 16' long and 18" to 20" through, I have sold about 75,000 board ft of lumber and it was all taken out by my JD 4400,I have broken things on my tractor,but the engine and hydro have never failed or shown any sign of failure yet.

 

[keeney]

There are lots of other things you can do with the hydraulics to overheat the fluid, even without using the hydro.

In my opinion, any kind of continuously loaded hydraulic-driven implement like a trencher, snowblower, broom, maybe a hydraulic PHD can easily overheat the hydraulic cooling system of many CUT's. Heck, just stalling the loader and letting it pump full power through the relief valve can do it.

I don't think that the oil cooler is big enough on most of the CUT's to take the full power of the engine dumped into the hydraulic oil as heat. Some have pumps that are able to supply almost full engine power to the hydraulics, but that is generally intended for intermittent use. An oil cooler big enough to dissapate the whole engine output would need to be as large as the engine radiator! (An Internal Cumbustion Engine typical dumps generates heat in a 1:1 ration as to what it puts out the driveshaft as mechanical power.)

Ignoring the hydraulics, I wopuld be curious to know if most modern CUT's even have engine cooling sufficient for 100% power at 100% duty cycle.

I would agree that a set of temp gauges for engine oil, engine coolant, and hydraulic oil would be most helpful in determining if any part of the machine is overheating.

- Rick

 

[eee]

Hey...my hydro has over 1500 hours of hard use,all kinds of weather and still going strong.
Evryone has opinions,I haven't seen any facts that says hydro's don't hold up.

 

[SCDolphin]

I wanted a hydro for fel work but I will also be pulling a disc harrow and a box blade. The JD dealer said he did not recommend a hydro for those activities. Any thoughts?

 

[eee]

You will not have any problem with your hydro,just keep the fluid level maintained and changed per your operators manual.

 

[Bird]

I didn't have a disc to pull, but I sure used my box blade a lot and was very glad I had the hydro. And I put up to 11 hours in a day running a brush hog at PTO speed with no problems. When brush hogging tall stuff for extended periods, I did stop occasionally to brush the debris off the front end of the tractor when the temperature gauge would start to rise a bit.