Help! My Jeep Is Moaning!

[alay73]

I have a 99 Cherokee Sport automatic. I am new to having 6cyl 4.0L motor. It makes a moaning sound that gets higher in pitch with acceleration but its not really loud. Just wondering if this is normal or could there be a problem with one of my pumps or trans. If its normal, What is it?

[MagicRat]

My first guess would be the power steering pump....next would be the transmission pump if automatic.
Does it decrease in pitch when the transmission changes to a higher gear and the engine revs drop?

[alay73]

The pitch seems to follow RPM. Ive only had this car a week so I cant say if the power steering has changed. Is there an easier way to check that beside putting in a new pump?

[MagicRat]

Remove the power steering belt and run the engine. If the belt also turns the water pump, run the engine for just a few seconds, and see if the noise goes away.
If it does, then it means the noise is coming from an accessory that is driven through the belt. Usually, other accessories make a squeal or a rattle noise when they go bad. The PS pump is the only one that moans.