I have been doing a lot of searching on this site concerning a vibration that started on my '03 3500 standard output srw 4x4 auto, at about 81,000 miles. From doing a lot of reading here, the symptoms are pretty much exactly like those of other owners where it would occur most noticeably around 68 mph but was still present at other speeds.

I had the rear u-joint replaced about a day after I noticed the vibration started because it had started clunking pretty bad and I thought it could be the problem. It helped a little bit but the vibration was still pretty bad, so I ended up taking it to a dealer. They found the rear driveshaft to be bent. So my question is why? What causes a driveshaft to bend? About 8k miles ago I went from the standard 265/70-17 michelin's to 285/70-17 BFG All terrain TA's. Would the increased traction create added torque to the driveshaft under hard acceleration? I haven't made any other changes to the truck and can't think of anything to cause the driveshaft to bend.

Also, I had to drive the truck about 800-1000 miles because of my work schedule before I could take it in to get fixed. Could this have caused any additional damage? Right now it's at the dealer waiting for the driveshaft to come in and they quoted me $550 for parts and labor, plus a loaner vehicle for as long as it takes at no cost. Are these just cheap driveshafts or is there any chance of Dodge covering any of this? I know my warranty conveniently ran out at 70k....good grief. Any comments would be appreciated.

 

It has a aluminum driveshaft and I am pretty sure bigger tires dont cause driveshafts to bend. Only thing i have seen bend or brake driveshafts are gators (tire treads on the road), bumping something or off-camber wheeling. The old steel driveshafts would be able to take more abuse but these new aluminum ones arnt as strong. Sacrifice strength for weight. And get that thing out of the dealership, I know around here there are drivetrain shops that will re-build yours for about $200 or for a new steel one will about about $300.

 

'03's don't have aluminum driveshafts. As to what bent it, who knows. How much was it out? And have you been in any situations that might have caused it?

 

When I lifted my old truck I had to have some custiom driveshafts made.. they we less expensive than the stock ones and alot stronger. Check the area for someone who makes custom drivelines.. Also make sure they have a good ballancer at the shop and it isn't just some weld/fab shop slapping it together..

 

I don't know how far out it is, but I can find out, and the dealership said they could see it wobbling when they ran it on the lift. The only thing I can think of that I might have done to cause it was haul a load of fire wood about the same time it started. But I have hauled PLENTY of firewood in this truck before with never any problems, and it hardly even moves the springs. This recent load wasn't even that full either. I'm just baffled.

 

When you are driving it does the vibration come from in the steering wheel or assometer? or is it so bad that you cant tell? Does it come on at 24 mph(40kph)?

Everyone is different as to how they feel a vibration. There is equipment out there that will help with this problem.

The best bet is to take the truck out and drive it with EVA(Electronic Vibration Analizer) and then take the information and enter it into Vibrate(software program). It will tell you what is vibrating and then you can take it from there. I know from when i worked at ferd that most dealerships have it. I dont know if dodge has this(or that it is a manditory tool). I know that in the future i will own both of them myself because vibration is a major pain in the butt(assometer(sop)).

Good luck on you vibration.

 

The vibration was felt mostly in the floorboards, seat and center console/seat and started about 45 mph and continued on up through 75 where I wouldn't really go any faster. The rear view mirror would vibrate so bad I couldn't see anything. It would smooth out a little above 70mph. Hopefully the driveshaft is the cause. Like I said, something all of a sudden went wrong because the truck was fine until now. So far it looks like nobody knows what would cause the drive shaft to bend or warp like it has. That's really what I was trying to find out through this thread.

 

I think Sevir HAS answered you're question. A driveshaft won't bend under normal driving/towing. Most likely you answered your own question in your first post:

There's no bad cars anymore, just bad mechanics.