We have a 2006 1500 Big Horn with the 5.7 HEMI engine, 4x4. Just past 70,000 K and it has developed a very loud whine (not high-pitched) when accelerating at all speeds, and it is sluggish when speeding up. The noise stops as soon as you stop pressing the accelerator pedal. When listening for it with the hood open, it appears to be located dead-center somewhere opposite the fan. I'm not sure if this would be an alternator or transmission problem or maybe something else. The belt appears to be good still. Also, the gas mileage has dropped from 18 down to 14.5 over the past months.

Any ideas of the cause of this problem? Could it be in need of a good tune-up or possibly have an air flow issue?

 

water pump or power steering pump my guess

 

Welcome aboard!

Whine is often power steering. Alternators whine, too. "Dead center opposite the fan" ... sounds like the rear of the motor?

 

I don't think it is power steering or water pump. The whine is not there when the car is idling or when it is turned on, and all gauges are at normal on the dash. There doesn't appear to be any leaks where it is parked and the steering is normal and responsive. It used to "take off" when you just touched the accelerator and now it takes longer to get up to speed. The whine noise almost sounds like air being forced through a crack and it can be heard over the top of the engine roar.

 

What does "Dead center opposite the fan" mean? Whining comes from parts that spin. Could this be a whistle?

 

Welcome to the site. The best thing to do IMO is to pop the hood and get under there and listen. Let a buddy or the wife rev the engine while you listen. If you need to, go buy a mechanics stethescope to help you identify what it is.

At this point it could be anything that rotates which means alt, ac compressor, idle pulley, water pump, ECT

 

I have a 2003 1500, 4.7L, 90000 miles. Mine starting making a whining noise after I ran through a huge puddle on the road during a thunderstorm (been a while since this happened). Sounds like bearing squeal, so I changed out the belt, idler and tension pullies, and had the AC compressor pulley changed out. Still makes the damned noise! I have yet to figure out what it is...local dealerships want $700+ to change out the power steering pump, so definitely won't be doing that. There's no play in any of the pulleys i didn't change, and the truck runs fine other than the noise...had a mechanic take a stethoscope to it and that's when i had the AC pulley changed. Noise was still there. Could it be as simple as changing out the Power Steering pulley? Also, you can hear it faintly at idle on mine, but its really loud when giving it any throttle at all. kind of winds down as the rpm's lower too. IRRITATING problem! any ideas????

 

Pulley on the alternator was the source of my truck whine. Take the belt off, or loosen it enough, and turn the pulley, mine sounded like it had gravel in it instead of being smooth when turning. You can probably rebuild replace just the pulley, I replaced the alternator w/ one from the local parts house.

 

I gotta ask, when was the last time you cleaned & inspected your throttle body/intake? Something come loose, not get put back on right? Tune up recently?

 

My whine was the alternator at about 57,000 mile. It occured shortly after I cleaned the engine. Taking a short cut to save some time toasted the bearing.