I have a 2004 2500. It has 46000 miles and I have a underbody vibration. I took it to the dealer and they said I have a blown baffle in my muffler. I went out and got a Magna flow muffler and I still have the vibration. It only happens when driving around 2000 - 3000 RPM. When I have it in idle and rev it up I get no vibration. I checked my underbody heat shields and they are all tight. Does anyone have any idea's what it might be?

 

Possibly the universal joints in the drive shaft. Mine lasted for 67k, but they can go bad sooner.

 

Thanks, Im bringing it to the dealer on Friday. I'll post again when I find out whats up.

 

I took it in on Friday and they still cant figure it out. They put it up on the rack and cant find anything loose. Its driving my crazy and the dealership told me they want it to get worse before they can figure out what the vibration is coming from. Im pissed!!!!!

 

do you feel the vibration in the seat or in the wheel at what speed is it happening if you feel it in the seat the rear tires maybe out of balance in the wheel the front tires maybe out of balance Also the u joint may have lost a pin bearing causeing it to chater which will cause a vibration this will not cause the u joint to show movement so the dealer my not find it if they are nit looking for it

 

I'm not sure if I feel it more than I can hear it but it sounds like its come right underneath me. It only happens at 2000 -3000 rpms then it goes away. It comes and goes to. Sometimes it always happens..ThenI can drive part of the day and then I wont hear it. Please post back...thanks

 

This sounds familiar. Check the Cat. On my old jeep, the guts blew out of the cat and it sounded like the truck was gonna shake apart.

 

if it comes and goes the pin bearings in the u joint can shifted causeing a smooth rotation of the drive shaft and there will be no vibrations then when they **** back they will start the vibration again the only way to correct this is to replace both u-joints
But first do the CAT. thing that that other guy told you about try to shake your exhauest and see if you hear anything moving it wont hurt to do that it free (But I would think that would make the check engine light go on or stall the truck because the emission cant get out if the insides clog it) My Father in law had a simlair he thought it was the tire and it ended up being the u-joints

 

when they shift back (sorry)

 

After 3 months of fighting with the dealership, they finaly replaced the CAT and the underbody vibration is gone. I brought the truck in 5 times and keeped on getting the same response "we dont know what it is". I copied and pasted this string and sent it to the along with a few nasty words to the Dodge Corporate office and my local dealership. They called me back immediatley and they said "we think its the CAT"..Well no ****...I guess they got the idea from you guys that posted your suggestions on what may be wrong.

Thanks for all of your help

Dodge Ram 2004 Hemi
Black
Magna flow Exhaust / AEM Air Intake