So lately my P/S has been making alot of buzzing noise when I turn the wheel. Fluid level is good and was changed about 20k ago. I have a 94 sc400. Does it sound like my pump is going out or my p/s rack?

 

If fluid level is going down and there is white smoke coming from the exhaust, then you have a failed vacuum valve, the PS pump also will do this when low on fluid, but if level checks out good then the PS pump could be worn out.

 

Yeah if the fluid is not depleting then its a pump on it's way out. Mine's been doing the same thing for about 2 months and recently getting worse and harder to hold the wheel while turning. It's last leg..