Hi All.

Over the last week or two I have noticed a whine noise coming from the front of the 140k mile 1999 Durango SLT 4x4 5.9L. I gathered a bunch of data, and am confused about the results. I am hoping someone on the forum might have a better idea than I do...

Symptom(s)
A whine-like noise that comes from the general vicinity of the engine compartment. I cannot tell if it is from the engine, cooling system, or drivetrain. The whine sounds roughly like the noise the power steering pump makes when it is out of fluid (that said - I do not think it has anything to do with the steering pump).

Data:

• The noise is present in 2WD and 4-HI.
• The noise is RPM dependent. Louder as the RPMs increase.
• Noise is not as noticeable at 30+mph. (It might be drowned out by road noise, so this is not that reliable of a data point)
• Noise is present during steering/turning.
• Steering/turning does not alter noise.
• Noise is louder in reverse than in drive.
• Noise is present (at a low volume) while truck is in reverse with brake applied, and hence not moving. Meanwhile, with the truck in Drive with brake applied - the noise does not occur.
• Noise stops if shifted into neutral (even while truck is moving). Throttle setting does not matter.
• Noise is not present when truck is in Park and engine revved.
• Noise is not there after a cold start.
• Noise seems to start approximately when the engine temp gets up to the ~192 deg thermostat temp.
• Once the noise 'arrives' it does not go away until the truck has had a chance to get back down to cold temperatures.

Looking at the data, esp the fact that a cold start does not exhibit the noise (for a few minutes), I am tempted to think it is a water pump or fan/clutch problem. But, if that is the case, why doesn't it make the noise when the truck is in Park or Neutral?

Okay, so onto the drivetrain. I checked the transmission fluid level and the rear differential - both ok. I need to check the front differential level (is this possible without removing the belly/skid guard? It looks like I might be able to reach in via the driver side front wheel well.).

Last, I am pretty sure my truck has the towing package, which I believe means it has a transmission cooler. Is there a pump for it?

 

First, yes you are correct that based on the information given, does not sound like a power steering issue. You state the noise goes away when it's in neutral so this tells me it is not an issue with a wheel bearing.

Also, you say it doesn't do it while it's in Park and revving it up so it makes me believe it is a transmission issue. When was the last time the fluid was replaced?

Yes! The "Trailer Tow Group" includes 160 Amp Alternator, HD Cooling System, and as you guessed Auxiliary Transmission Cooler. Check the lines going from the cooler to the transmission itself and ensure there's no leaks or anything that looks out of the normal.

If you're feeling lucky, I'd try getting a friend/wife/girlfriend and put the rear end up on jack stands and hit the throttle as if you were driving (in Drive). MAKE SURE IT IS IN 2WD ONLY! Get under the vehicle and isolate the problem where it is coming from and most likely pay attention to near the transmission area, that's what I'm thinking it is.

My first possible solution would be to start by doing a full transmission fluid replacement and checking the pan for any signs of anything wrong such as metal in the pan or inconsistent fluid color. When you do a fluid change use nothing except ATF +4, I've heard of problems like this due to puting the wrong type of fluid in.

Also, since you claim the noise mainly comes around when the engine is up to full operating temperature, it may be the Torque Convertor. Try driving with the O/D OFF on the gear shifter pressed in to turn off the Overdrive gear and see if that possibly helps.

 

also check the fluid in the t-case

 

What about a bad vibration dampener or worn main bearings?

 

Front pump on the trans would be my guess from the description. They can sound like a failing power steering pump when they begin to have problems.

 

I'd check the tranny fluid and replace along with filters. Mopar or Valvoline ATF+4 only. Transfer cases 75w90. If you're gonna do the jack under the rear route, make sure you have dependable chocks under the front tires!

 

Hi All. Thanks for the suggestions. I double-checked the ATF fluid (with the parking brake on, vehicle in Neutral, transmission warm, and on a level surface) - and it was about a quart low. Unfortunately, adding the quart of ATF+4 back did not seem to help. The fluid on the trans dipstick seems to be in okay shape. Still reddish/pink and does not appear nor smell burned.

I took the truck for another test drive yesterday. The sound is definitely not there until the truck gets up to ~185degrees (per my OBD monitor).

I still need to check the front differential level as well as the transfer case. It is probably time to service both of them as well as the transmission fluid.

I am pretty timid about putting the truck on jack-stands, even more so if I have to get underneath it while it is running. It would be great to diagnose the location of the sound, but my life preservation instinct just will not allow me to do it :-)

Wouldn't it be cool if there was a 'do-it-yourself mechanics shop' where you could rent time on the lift by the hour or day?

 

Now I have a similar situation. It may have been covered in the previous topics but i need to ask, whenever I'm driving and keep it steady at a constant speed it makes this howling sound. Now have some guesses but just want to see what you guys think.

 

Jaz, when you turn the steering wheel while you're driving does it change pitch/tune? If so, wheel bearings bud.

 

Widow- well i haven't tried that, i'll try it on my home from work.

What happens is i can be going 65 and after i keep it there for about a couple of minutes you can hear the howling.. then if i take my foot off i goes away. it also doesn't do it while on cruise. I'll check the wheel bearings though.