I see there is much discussion about the drivetrain howl. I have experienced it (I believe) but I thought it was a sticking caliper making the brakes get hot...(or something) It did only happen when I got on the accelerator...and going low speeds like 20-40mph. But, it only happened after everything was warmed up. then seemed to go away after a while. Also, much more noticable when I was towing my 5th wheel. (8900GVW) I've had mixed experience with my dealer, although so far they have not complained too much about warranty repairs. (nothing compared to my previous experience with GM...but that's a whole other story )
So, does this sound like the rear-end howl/whine that everyone is talking about? Also noticed that there is a TSB concerning this but only applies to 4x2, not 4x4. Anybody have the number of the TSB so that I can mention it when I take it in for service?

 

Anyone?.....

 

Might be a J-joint going bad? I had that same type of thing happen on my '03.

 

My 03 does it too. But so does my 77 Scout, and it has almost 200,000 miles with no problems. So I haven't worried about the truck.

 

What's a J joint? Sorry, I couldn't resist. In all seriousness, checking the U joints is a good suggestion-it could very well be one of those.

 

Hrmmm, what is a J-joint. I didn't even notice my typo.

 

A u-joint will never make a howling noise. They will "chirp" like a baby bird when they are out of grease and wear out but never howl.... ever. Any howling is rear/front end related(may also be bearing/bushing in trans or t-case) but in these trucks very rare. Howling is usually the rear end ring and pinion gear contact parrern. Could be installed incorrectly or not ground perfectly to match each other. This has been an issue for the AAM rear ends unlike the Dana. But I am sure Dana went thru this way back when (probably in the 1960's before most of us were driving) and they figured it out and then many years of mostly trouble free service. AAM is a good strong axle and after some refining it will be a great rear end. Just a learning curve for them. Also keep in mind a dealer will not want to cover it and try to say its "normal for this heavy duty truck". So ask them to go for a ride in any other "heavy duty" truck on their lot new or used and listen for any howl. They may do it then. If not go to another dealer and try. But dont tell the new dealer you were somewhere else before, just go like its the first time. I have many threads on this as I have had 4 rear ends under warranty last year in the same truck for this reason.

 

The problem is that is is so sporadic that I'm sure that it won't be making the howl when I take it in and I'll get the typical response "Cannot duplicate problem"...Like I really wanted to waste a few hours and bring it in for repair that I made up in my head!! I'll guess we'll see what happens.
thanks

 

I seem to have the same problem, the noise sounds just like when you blow into a pop bottle, much louder when I tow my trailer, but very random will go days without doing it, I am going to start from head to toe on my truck this weekend to find it, I will let you know if I find anything that may help

 

I found the noise, it was a rear brake caliper hanging up just enough to cause a harmonic noise on the rotor

 

What did you do to fix it?

 

removed the slides, cleaned and regreased them and put on new pads, the others had worn down at a angle due to the bottom slide being tighter than the top so they would release at a angle and the noise was from the bottom of the pad still making contact every once in awhile, the bottom slide was pretty dry but did not have any scoring on it so I was able to reuse it

 

The rearend in my truck has always howled a little when cold from the day I bought it. A few miles down the road and it stops. 97,000 miles later it does the exact same thing every day.

 

Mine started to howl on a 200 mile weekend trip, once, while pulling my TT. Every time I was going uphill and caught a bounce in the truck it would howl like a banshee. I would suspect the pinion angle changed starting it. If I let up on the throttle it would stop but if I got on it again too hard it would howl again. A bit of a nervous trip thinking it was going to crater on me. It quit on the return trip and hasn't happened since. That was 50K miles ago. I actually believe in ghosts.