</font><font color="blue" class="small">( However, I understand the point you make, but I believe that you have missed mine. I am concerned about a new noise that was not there for the first 24 hrs of use; a noise that translates a vibration at a similar frequency to the whine through the steering wheel. )</font>
...and I hope you won't take this the wrong way, but it's hard to figure out what you are asking because you said in your first post in this thread that automobiles don't make these noises, and I just tried to explain that they do. Because of the design of their steering system, you don't get the extra noise translated up through the auto steering column. If you listen to the pump and steering box on an automobile, you definitely hear a "groaning" type sound that increases when the fluid (normally ATF) is cold. Now I see you actually want to know how your system could suddenly start making more noise and vibration than before. That's a good and valid question. Okay, I'm going to give that a "stab." /forums/images/graemlins/wink.gif
In your other thread and in this one, you never mentioned that your tractor is a TC25 and that it's power steering pump is not run by a belt-pulley arrangment, but is gear driven off the engine. You also didn't establish that your filter is actually a reservoir and to change it required draining and disassembly rather than a spin-on filter. That's why JerryG in the other thread gave you bad info. There was no way for him to know what you have.
I'll ask for you... <font color="blue"> Have any of you who own a TC25 had similar symptoms? </font>
I believe the way your system works is your steering column is directly connected to a steering valve/pump. There is absolutely no mechanical connection between your steering wheel and your front axle, only hydraulic lines. When your engine is off, you can turn the front wheels, but only with great effort because the steering wheel powers a pump to push fluid out to the hydraulic steering cylinder. When the engine is powering the pump, it takes over all that work and when you move the steering wheel, you more or less open valves and direct fluid in the proper direction to power the steering hydraulic cylinder.
Okay, all this to say that those valves are tight and stiff when new and as your tractor becomes broken in, they might start to make more noise as fluid passes through. Of course it could also be a problem like air getting into the lines causing cavitation as Soundguy and others have correctly suggested.
I would make a check of the fluid level in the reservoir and the hose coming out the bottome to make sure it is tight. If it's not leaking any fluid, it's probably tight. Follow that line and check all the fittings all the way to the pump to make sure they are tight. Hold your hand on the pump while getting someone else to move the steering wheel (if you can't reach it). Try to identify if the noise is coming from the pump or from the steering motor/pump in the steering column. Also check to see if the noise goes away as the tractor and fluid warms up. After that, you could call your dealer and talk to his service manager with a full description of the symptoms and what you have checked. That will help him determine if he thinks you need to bring the tractor in for a checkup.
Also, you might send a PM to MikePA. He also has a TC25 and can probably give you a good idea of how his steering works.
I really hope you find your problem. It can be really frustrating to have something crop up and make you wonder if it's a problem or something you should ignore. Remember, nothing is a substitute for a full description of the tractor and the problem. You'll find lots of expertise here if folks know exactly what the problem seems to be and the exact configuration of your tractor. /forums/images/graemlins/cool.gif