I have had two problems with steering noise on a 940. The first was a clonk and notchy feel when turning the wheel. That was fixed by a independent dealer who I think replaced a worn track-rod end, but it was a long time ago and I'm going by memory. It may have been a UJ in the steering column.
On another occasion I became aware of a sort of grinding noise when turning right at a particular roundabout on the way into work. This was cured by getting the fluid level right and ultimately by renewing the fluid.
Looking to see if I'd ever posted what the fix to the first problem was I came upon this old thread which suggests another possibility. See post #5.
https://www.volvoforums.org.uk/showthread.php?t=194321
I have found that keeping the fluid clean and topped up, periodically using maintenance spray to clean/lubricate the accessible UJs in the steering column and keeping the belts in good order and correctly tensioned has avoided any recurrence of either issue. The garage that does my MOTs is pretty good at spotting and replacing worn track rod ends.