I have an 01 S60 T5.

I was at a reputable mechanic getting my car safetied and one of the things he did was to "Free up steering shaft"

Before the safety, It was hard to steer and almost felt like there was no power steering or worse. He said it was seized and he freed it up.

Anyways, this problem has come back again. I talked to him and he said he could order a new steering shaft and put it in for me, as it would cost just as much or even more to rebuild it.

Could anyone tell me where i could find this part and if there is another name for it? I have no idea what it is... and neither do other people ive talked to. Also is this something I could easily do myself? I had a honda before ive done repairs on and this is my second car.