For some time now I've noticed a clearly audible 'humming' noise that appears to come from the rear side of the car. The only way I can describe the noise is to say it sounds similar to an airplane-type noise. My guess is that maybe it's an issue with the fuel pump, filter, or the electrical system that powers the fuel pump. Is there a way that I can tell for sure which is the case or even if this is the correct diagnosis? Also, where would be the best place to buy the parts myself since I don't like having the dealer charge me for parts?

 

are you sure its not a wheel bearing. is the noise constant or when turning. also the rear diff is just sometimes noisy. if its a wheel bearing it will quiet down when you make a left or right turn depending which side it is. a fuel pump or clogged filter will usually result in sputtering, hard starts. misfires and other engine issues. as for the rear diff, try replacing it with thicker or different oil, my rear diff had the factory oil in it (170k) and it was toast when i changed it. the rear diff now hums a little less now that i got some fresh lucas oil in there.