I'm not really sure I understand exactly what tough means? Does the wheel get hard to turn? Are you turning it all the way to the stops either way and getting a squeal? That would be usual, the squeal, but not difficult turning at that RPM.
Are you having any difficulties with any other hydraulics such as the 3pt hitch or the HST?
Now tight turning often will cause you to turn the wheel all the way to the stops, and this should not be maintained at full turn for a long period, but it should make it difficult to turn, but will make a different noise.
You've had it long enough to notice the difference I would suppose, so if you think there is a problem, the first thing to do is call the dealer. If there is a problem, you need them to repair it anyway.
Unless you have someting bent or broken, I can't think of any reason you should have difficult steering if everything else is working right, and you say it seems to operate properly if you raise or lower the loader, which is a little confusing. Does it turn okay in open territory? That model doesn't have a separate pump for the steering, so it should work as well as everything else.
Let us know what's happening. and if you can, describe exactly what you're getting, when, and what you're doing in ever instance that you have a problem.
John
