Engine/Transmission (1998.5 - 2002) Curious noise

[billjackson]

My 2002 Ram 4WD Automatic recently developed a growling sound at approximately 1000-1200 RPM. It sounds like the power steering pump is low and actually creates a vibration through the steering wheel. It only occurs after the truck has been driven to full warm up and turning the wheel seems to amplify the sound, although at the 1000-1200 RPM range it does it in a straight line, regardless what speed or what gear it's in. If I accelerate above or fall below that RPM, the sound goes away. If I'm turning a tight radius at low speed (1000-1200 RPM) it gets real loud and definitely sounds like the steering pump. Sitting at idle the wheel can be turned from stop to stop without a sound from the power steering pump. So, I replaced the steering pump (no leaks at the vacuum pump at 158,000) with a napa remanufactured unit, installed napa steering fluid and no change... ... ... What's next?... ... ... ... . Vacuum pump?... ... ... . any ideas? I know the members here have been through it all so your help will be greatly appreciated.

 

[azpartsguy]

I have the exact issue right now did you ever figure out the problem?

 

[KATOOM]

Strange that it didnt change when you replaced the PS pump. Because noises like you describe are a result of PS fluid getting old in bad need of replacement. Power steering fluid is the least maintained lubricant on a vehicle. No one seems to look at it ever unless there's a problem. And because the hydro-assist system on these trucks runs very hot, its a really good idea to change out the PS for some quality synthetic stuff. Usually that results in quiet smooth steering and braking action.

When you're hearing a noise from the engine area, something you can do to pinpoint the source is to use a "mechanics scope" which is essentially like a doctors scope, or just take a dowel or small broom handle and hold one end in your hand up against your ear and the other end touching specific parts. The noise will transmit directly up the solid stick and you can identify if whatever you're touching the stick to is the noise maker.