Need Help With Noise

[Don Edmonds]

Maybe someone has an idea. I got my 2003 2500 shortbed in early April and from the getgo it whined between 50 & 55 mph. Not much before and not much after. I figured it was the rear end and at 1000 miles the dealer agreed. They said the factory said drive it until 5000 miles and see what happened. Ok I did and the noise was still there. So! a new differental was ordered and installed yesterday (10/2/03) no problem. But the noise is still there at exactly the same spot, 50 to 55. Its obiviously a new rear end, housing and all, clean as a whistle, same brakes and wheel bearings. I can't belive that a new unit would make the same noise at exactly the same speed. It must be something else. Does anyone have any ideas. I ask them about the drive shaft, the tech. said steel maybe but these shafts are alum. and he didn't think they would be noisy. Help.

 

[Prairie Dog]

Could be the drive shaft carrier bearing? Does it do it when you let off the gas and coast through those speeds? Does any vibration accompany it?

 

[DIESELMAN]

Originally posted by Prairie Dog

Could be the drive shaft carrier bearing?

Maybe the carrier bearing is missing , its a shortbed, shaft is one piece past the tail shaft isn't it?



When it howls at 50, does the howling pitch (tone) increase as you go through to 60 and beyond? or does it stay the same pitch and just fade away?



Does it howl the exact same pitch at the same speed in OD and 3rd?



Does it howl when decelerating and under load?



Is it quiet with your foot off the pedal?



If so, does it Howl if you drop into nuetral at 55? Thats nuetral, not reverse .



If the pitch doesn't change it may be a harmonic noise, body panel, exhaust, bed floor, bed front, fuel tank shield etc.



New differential was installed, but did they re-set the pinion depth or just replace the guts, if they didn't replace the pinion then the spacing could quite easily be the same, and so would the noise.



Mine makes some howl while under power, but the wear looks perfectly centered on the ring and pinion, so I'm leaving it alone.

 

[Steve M]

Are you sure it's not the DodgeCummins "wine glass chirp" that developes around 1750rpm? All of mine have done it. My '95 was the best. It's a deep spooky sound like when you blow across a glass coke bottle. But it's called a wine glass chirp because it kinda' rings as it does it. Hope that's what it is for you. It's the turbo resonating through the long large diameter exhaust.

 

[Don Edmonds]

Noise??

Thanks for the comments. The noise is only present when power is applied, not there when coasting. It's only present between about 50 and 55 mph then it's gone. The entire rear end was replaced so I doubt if they were inside the new one at all. It seems to be speed related as it's at the same speed in or out of overdrive. To me the pitch seems the same, hard to tell for sure. Don

 

[GWDiesel]

Alum.drive shafts

DonEdmonds, you might want to peek under your 03 and look at the the drive shaft,Mine are rusty,I wonder what that tech was thinking of ?? GWD

 

[Don Edmonds]

Drive Shaft

Funny thing, mines aluminum. It's non magnetic. Don

 

[GWDiesel]

Rusty Drive line

HI: DON My 03 is a very early 03 bought the week before Thanks

giving,So it looks like changes that I don't know about!sorry

about that! Jerry

 

[Prairie Dog]

Mines rusty too and I bought it at the end of Sept 02. I don't have any of the vibrations that so many folks complain about. Could it be the aluminum drive shafts causing all these problems???

 

[DIESELMAN]

I guess I need to crawl around at the dealer some, All the longbeds that I have seen have steel, and the couple of shortbeds that I have crawled under, have aluminum, at least shiny non magenetic.



Is this the case?



Maybe the aluminum is too thin walled and there is a certain amount of harmonic "whipping" going on?