Follow up: My JD dealer was out this morning. The squeak was in the steering wheel. Took wheel off, took boot off, clean and lubed up the shaft and a white plastic bushing. Squeak is gone. The noise I had sometimes when I turned the wheel is also gone. Don't know if that's the noise being referred to in this thread. Dealer agreed that the squeak would drive you crazy if you had to hear it all day. I told him if it drove me crazy it would be a quick trip to a familiar location.
I still hear both hydraulic and servo whine, particularly when wheels are turning hard or at the end limit but it's very faint and in the background. Sometimes listening in the cab with and without hearing protection lets you hear different things. It's not objectionable and is consistent with all the other little noise you hear. You get used to them, and it's part of the feel of the tractor and it's how you can tell if something is wrong.
I'm real happy with my JD dealer. The quality of the dealership was my 1st, 2nd, and 3rd factors influencing what I bought. There are good and bad dealers of all colors spread around the planet, and I'm lucky to have a good one near by. I've also bought almost all of my implements from him so we have a good relationship and he can stay in business. I'll pay a bit more to have just one company that I deal with that is making sufficient margins that it can own and solve my problems. The day tractor dealerships and tractor owners start treating each other as if it were the Wall Mart experiance we're all screwed.
Pete