2004.5 Drive Train Howl

[MJWenrich]

Some time back I posted a question about whether a howl I heard could be from a turbo. Following suggestions and not finding fault with the turbo, I decided to just drive it until the noise became more pronounced. That has now happened, but is still a mystery. I am now thinking that the noise is coming from the transmission but I would like suggestions of what could cause a howl, all the way back to when this truck was new. I have 113,000 on the clock and what I notice is that the howl is worse in cold weather and especially when I first start out. After warming up, it becomes less noticeable. It is heard only on torque but it changes pitch with rpm and power input, leading me to eliminate the rear carrier assembly. I had a great deal of work under warranty to eliminate this noise, even though the service rep could never hear it and I am hard of hearing. Ultimately, a drive shaft with a donut shaped collar wrapped on the shaft near the rear end quieted it down a little but I could still hear it faintly. When I open the rear slider, I can hear the noise much louder.



Could a torque converter howl? Or some other component in the trans? The trans shifts flawlessly and the oil does not indicate a problem. I'm just darned tired of the whining. I thought I was rid of that when the lids left home.

 

[p-Bar]

It's probably your rearend . There is a TSB on that and when I had the dealer drive they said they couldn't here . I should have pushed the issue figured I would lunch this one and install and ARB locker. I hear mine more when I am decelerating

Here is the TSB http://www.ramforum.com/50663-post64.html

 

[MJWenrich]

Although I have the 4x4 model, this is probably why they installed the drive shaft. But I am pretty certain the whine is from the trans. Or at least the noise is radiating to that area. I probably should get in the bed of the truck and have someone drive while I try to pinpoint the location. At least I would know for certain where it's coming from. If it's the trans, what can make noise on a 48RE?

 

[p-Bar]

Their are a few good trans experts online Cerb for one hopefully he will chime in

 

[cerberusiam]

Opening the rear slider just guarantees you will chase problems forever. There is a LOT of vide, reverb, harmonics, etc, in those boxes and it really gets amplified with the window open.

The typical problem in the OD transmissions was the OD planetaruy was worn and as sso as it hit OD you could hear the howl. It would run for many many miles like that with no issues but it was there.

Since you got it to partially go away with a balancer on the drive shaft it is probably harmonics causing it. The first thing I would do is put in the 1 piece drive shaft and add the 6. 7 harmonic balancer to the engine to see what happens.

 

[MJWenrich]

Thank you Cererusiam but This noise is heard in other ranges as well. It is the the worst in third range when cold, at about 40 MPH, on a slight uphill grade. I can hear it in second as well but I don't stay in that range long as I do my driving. Once into OD it diminishes and after warm up, the lower range whine is harder to hear. The noise goes up and down with rpm, and goes away during deceleration. This would be one of those noises that a tech would have to keep the vehicle overnight to really hear the worst part. I have just been reading about the harmonic balancer change but know nothing about the one piece drive shaft. How would that help and does it eliminate the harmonic collar on the present shaft that the dealer put on? I was mainly reading about the balancer because of the engine vibration I can feel in the 70-75 MPH range.

 

[cerberusiam]

The one piece shaft gets rid of the hanger bearing in the center on the extended cab trucks. If you have a standard cab truck not sure you have that bearing to be problematic.

The stock automatic drive shafts come with a balancer on them that is supposed to counter act the torsional harmonics that set up vibrations. It frequently goes bad and you have vibes.

If you have vibrations at 70-75 that you are chasing then there is something in the drive train that is causing it. A howl or harmonic or vibe under load is frequently in the rear differential, especially if it goes away under decel. Have you tried removing the rear drive shaft and just driving with the front in 4x4?

The t-case itslef could be the source of the howl also, not as usual as other things but a possibility.

It is so hard to define whether the noises are a result of a mechanical problem or harmonics. Normally in a good transmission you might hear a whine that is worse cold and disappears when warm from the pressure relief valve on the VB but it genrally does not disappear with decel.

If the harmonic balancer goes bad and slips there is no telling what kind of downstream vibe or harmonic will manifest.

 

[6speed]

How many miles? Have the u-joints been checked along with the carrier bearing? Is the vehicle lifted? I wonder if maybe the ring & pinion might be going bad. Usually a howl on decel goes away in this area.

 

[Prairie Dog]

Cerb. can you drive with the rear DS gone without fluid slopping out the hole?
I have a vibe at 75 I'm chasing now. .

 

[cerberusiam]

Cerb. can you drive with the rear DS gone without fluid slopping out the hole?

I have a vibe at 75 I'm chasing now. .

You an me both. I think my t-case has issues.



A 2 quart freezer bag and duct tape that sucker to the output shaft housing, thats what I do. Red Green taught me that. :-laf

 

[Prairie Dog]

You an me both. I think my t-case has issues.

A 2 quart freezer bag and duct tape that sucker to the output shaft housing, thats what I do. Red Green taught me that. :-laf

Ah man, I thought you had that fixed.
I almost hope it's the DS so I can have it worked on.
When I bought the Dodge 1 piece and had it shortened, I think the shop said they balanced the end that they cut. To me this makes it sound like the other end is still suspect. They also told me that the UJ's aren't centered very well by the factory and that the builder then just uses balancing to offset the poor centering and vibes. If that's true (and if I understood them correctly) then balancing would only do so much IMO. It would probably still vibrate at higher speeds.

Scotty

 

[cerberusiam]

I did fix a bunch of it with the new shaft and some other things. Have a slight vibe between 70 and 75 that is hard to track. Almost like a harmonic but I have some play in the t-case shafts so need to test a little more to see if I can narrow it down.

 

[Prairie Dog]

Mine comes on solid starting at about 74 and gets a bit worse and then mostly diminishes by about 80 but even up to 90 I can just barley feel it and see it in my mirrors.
It may have been there the whole time since I've had the 1 pc (I rarely get to drive at those speeds) or it may have been there since the Toyo's, which I just re-balanced. I'm just not sure.

 

[cerberusiam]

Mine is subtle and it hard to tell past the whine and harmonics of the worn out MT's. It is enough so I see movement in the mirrors and can feel a minimal buzz everywhere. Harmonics a bugger I have found. Depending on what exhaust configuration adn muffling things change. An exhaust leak will setup a audio noise that mimics a bad ujoint. Drove me nuts trying to find it. Redid the clamp and added another hanger and it went away. Since I don't have the balancer on the DS anymore I am thinking some of this might go away with a viscous damper, that is a next step.

 

[MJWenrich]

I have the extended cab and 114,000 on it. No play noticeable in the UJ's last time I checked and the howl was there then. This has just been a progressively louder howl as it ages and is worse when cold. I climb about 500 feet elevation when leaving home and as such, I am on acceleration all that time. By the time I get to the nearest town, about 7 miles away, up and down hills, the noise has diminished. Still there, but much less noticeable on torque. That is why I have questioned the converter or some other component that might be affected by trans temp. Had not considered running on the front wheel drive without the drive shaft. That might tell me something if the noise is gone... but I'm not sure what it would mean for diagnosis. It's probably something I should do or just drive with ear plugs as it worsens and eventually something will break. Thanks for the input and help. The one piece drive shaft might be an answer as well if others are having trouble with the two piece.

 

[MJWenrich]

Forgot to add that my truck is bone stock. No lift kit or oversize tires, etc.

 

[cerberusiam]

Mine did somewhat the same thing as it aged. Afte rit passed 100k it started with a cyclic noise\vibe\harmonic that steadily got worse. Changed all the ujoints and did not effect it. By the time it got to 160k or so it had some weird reactions to throttle input and depending on the road it would act like a tire was out of round. Changed to the 1 piece DS and 90% of the noticeable problems disappeared. Still have what is a minor vibe in small range that could be anything.