Slight noise under hood/60-65MPH.. Help!

[DPKetchum]

The HVAC doors etc. are ALL electric.

 

[roperteacher]

Is it possible for the rear-end to WHINE only at certain speeds? Also, is it possible for the rearend to whine and not whine depending on if you are on the throttle or not? Just curious. Thanks foir the help! I read over lots of threads on here about rear end whine... the far majority are basically saying to just get used to it and that DC says the noise is normal? Please confirm. Thanks again! Oh, the truck must have known we were talking about her, drove to town last night and it BARELY made the noise!

 

[roperteacher]

OH, YES, the truck came with the updated hydro boost hose. I checked it yesturday. Has the big "C" shaped weight on the hose coming from the power steering pump!

 

[MCornwell]

Originally posted by nickleinonen

i hear my lift pump every morning before i start it, but no vacuum pump

I know what my lift pump sounds like , and this is another little



motor going about its business. Sounds like its getting



progressively louder so i might be in for a new vac pump...



Its runs for about 8 secs or so then turns off and i dont hear it



agin until the next cold start



-Mitch

 

[rbattelle]

Now, Dean Upson is normally very very reliable for knowledge, but I think he's wrong. I'm with Wayne (Amsoilman)... there is no evidence of any vacuum pump on the '03, either in the service manual or by visual inspection of the area behind the heater controls.



Here's an intersting idea, roperteacher... is your accelerator pedal vibrating? In very early '03 trucks, there was a problem with some of the accelerator pedals vibrating at highway speeds. To some ears, it sounded like it was coming from the hood. Putting a slight pressure on the pedal stopped the vibration. You might check out this thread. Also this one.

 

[roperteacher]

I'll ck out the threads thanks! And no, I feel no vibration on the pedal. In fact it is the OPPOSITE... the noise goes away when I let OFF the pedal, not step on it. Thanks for the help!

 

[SRadke]

The service manual refers to DC electric servo motors that activate the mix air door/s so if threre is a vac pump I don't know what it does. It also states in the service manual that the vacuum reservor is on the trucks with gas motors only. I dunno?



-Scott

 

[BSchulte]

I am having the exact same issue with my 04. I appears to start whineing at about 62 mph. , and lasts up approx. 66. At 1st. I thought it was the rearend howling. However, I realized that the sound appears to be coming from my right and under the hood. I had it checked out at the dealer, which they also heared it from inside the cab. But, found no issues within the drive train. I strongly believe it is something that is rotating inside the engine compartment. Fan, compresser, wastegate noise, natural air flowing inside the compartment, heck I don't know. Something interesting, I was driving home today from a weekend trip with a strong tailwind. And I did not notice the whine hardly at all. So I deliberately turned around into it, and noticed a considerable noise change. I do not think it's the turbo because it appears to not make the sounds when the turbo is spooling on steep grades at lower speeds. I don't think it's anything be too worried worried about. But I agree, it can get anoying

 

[MCornwell]

OK GUYS

There is a vacuum pump on the diesel with a AUTOMATIC trans,



not one on the manual. It controls the speed control servo. It



clearly says that the manual speed control is by the ECM only



(servoless).



its on page 662 on my [03DRM] Acrobat shop manual.



There is no reservoir, so that explains why i hear it every cold



start.



-Mitch

 

[roperteacher]

B Shulte described my noise to a tee! I also notice he drives a silver colored truck, mine too, maybe thats it... all the silver ones talking to each other... LOLOLOL It is ANNOYING..... Thanks for all the replys...

 

[amsoilman]

roperteacher,

I have to ammend my first reply regarding the vacuum pump.



After thouroghly looking in my repair manuel, I found out some more information on the Vacuum pump used on some trucks with

Automatic Transmissions .



This is what it states in the manuel:"3. 7/4. 7/5. 9/8. 0 Gasolene engines and/or DIESEL with Automatic use Vacuum for the speed control servo. It also states:5. 7 L engines are SERVO-LESS! (NO VACUUM)



Also stated:5. 9LDiesel with automatic Uses a Vacuum Servo with an Electric Pump but NO RESERVOIR! the gas engines with a Vaccum system have the RESERVOIR!

The Vacuum pump is lmost likely located in the ECM But is not mentioned as to its location, other than the ECM is where everything takes place on the Diesel engines.



Dodge has really confused ME! on this one! Why the different models use different ways to operate is beyond me! My truck is a 6-speed manuel, so it does not have a Vacuum Pump.

 

[dkosheba]

I have noticed a noise as well in the same speed range. Just took a 2900 mile trip and got a good ear full and believe it to be the High Pressure fuel pump on my truck that is making a pump noise. My first thought was injector noise, but after some time I now thing I can actually hear the noise the pump or gears make that turn it.



But, I really don't know anything any how !

 

[roperteacher]

Truck is in the shop currently for the noise and dark Rear diff fluid color! I'll let you know something today!

 

[rbattelle]

I'll take this opportunity to point out that for the first few thousand miles my engine made such a racket at 2000-2100 RPM that it physically hurt my ears. Granted, I have excellent hearing and my ears are very sensitive, but nevertheless that's loud. Both me and my wife agree that it's FAR quieter now with 21000 miles on it!

 

[draymorris]

I think it is the rear end

My truck is in the shop right now getting a whole new rear end. I think I have heard this noise since the day I drove it home - it only got worse as I put miles on. My rear end has been making metal flakes the entire life of the vehicle. I took it in last week and they ordered a new one the same day. Not sure what they found yet, but I will talk to the mechanic when I pick it up. Your description fit my noise. I think that the gear meshing in the rear makes a noise when under the slightest load - I also think it resonates in the drive train and is very hard to pin point. I will see how mine sounds when I get it back.



Also, mine seemed to be louder in 6th, and almost gone in 5th, but the mechanic decided to replace the rear end first and see if the noise in 6th goes away. I wonder if he has seen this before.



BTW, mine has 67k on it and has been well used pulling heavy loads.

 

[JimP]

Noise

Roperteacher:



I would not be surprised to find the noise caused by the method dodge connects the throttle pedal to the engine. I have a 2004. 5 that telescopes general noise through the pedal. If I take foot off the pedal ,it stops making the sound, If I accellerate it stops.





JimP







2004. 5 4X2 Q/C 48RE 600/325,black& silver

 

[Blakers]

Originally posted by JimP

Roperteacher:



I would not be surprised to find the noise caused by the method dodge connects the throttle pedal to the engine. I have a 2004. 5 that telescopes general noise through the pedal. If I take foot off the pedal ,it stops making the sound, If I accellerate it stops.





JimP

I don't believe the throttle pedal is connected to the engine in any way besides electrically.

 

[DPKetchum]

Its not connected. Its a drive by wire setup.