1999 F-250 2Wheel Drive V10 114,000 miles. Fluid Change @ 53,000 and 111,000 miles. Torque Converter drain and new ford filter. I have developed a whine that is engine RPM specific that starts around 2100RPM and will increase in volume and pitch to around 2500RPM and then decrease until 3000RPM. The whine does not occur until reaching operating temp. after about 3 or 4 miles. Any gear, Neutral, Park. The whine is a tubine whine. Doesn't sound like a front pump. One last symptom. I can produce the whine, for example, in 2nd gear around 2200RPM and hold that RPM steady. The whine sometimes will quit for sometimes a second or two and sometimes as long as 5 seconds, and then reapear at the same volume and pitch. Transmission shifts good, pulls good, etc. Any help would be appreciated.

 

Check the engine cooling fan real well.

They can make the same sound when they have failed or are about to.

 

Thanks. Have done that. Also have flushed the power steering pump. After I got it to be intermittent at a constant RPM that pretty much ruled out any component that does not have a valve or switch that controls a pumps pressure. I have also listened to the power steering pump with a stethascope. No whine. As a matter of fact, the whine is more pronounced in the cab than it is under the hood. Also replaced the serpentine belt thinking that it was hard and was developing a resonant frquency by the slight amount of flexing that all belts do. No fix. Thanks again for your thoughts.

 

O.K. Guys. Pulled the entire fan and clutch assembly off the truck today and did a test drive with just the pully bolted to the water pump. Same noise.. HELP.