'02 Dodge Ram 2500 4X4 6 speed CTD, 140K, Vibrates at about 75mph. Not bad but like you are going over minor road bumps. Took it to the dealer, they said start with tire balance and rotation, did that, didn't fix it. The mechanic said everything underneath looks good EXCEPT for the U-joint closest to the rear end. He said it's making noise. I figured I'd start there, even though the U-joints only have about 50K miles on them. I was just wondering if anyone else has run into this problem. Thanks.

 

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Ive heard it before. . .sometimes the drive shafts can be out of ballance, or the pinion angles are not right.

 

My truck was doing the same thing, had the dealer replace the rear u-joint and now the vibration is gone. I had the tires balanced first to rule it out. One easy way to tell is let off on the trottleonce you detect it, if it goes away it is probably drive line related. My truck only had 55,000 kilometer/30,000 miles.

 

I've got a vibration from 65 mph up. Haven't found it yet, the problem is it is intermitant. When I look for it, or try to get it to act up it don't do it. Got worse when I put the bigger tires on.

 

Were the new tires spin balanced or bubble balanced? I've problems before with tires bubble balanced, just curious.

 

How much weight did they have to add? I would check tires/wheels for out of round. While you have the tires in the air check your tie rod ends, steering link..etc.

 

Same thing happen with my truck. Vibration when letting off gas, was a very fast vibration, like a womans vibrator lol. Replaced u-joint closest the rear axle and all is well now.

 

Start simple with it, obviously the tire balance. Switch the tires, if you can, one at a time with the spare tire. If one of them is out of round, has a busted cord, or is flat spotted, it can help weed it out. Also, try rotating the fronts to the rear and vice versa. If a tire is slightly out, it will be worse up front.

You already said that you are checking the u-joints. Possible, but not likely.

Where I would start looking is at the ball joints and unit bearings. Jack one front tire off the ground and grab ahold of the top and bottom of the tire. Rock it back and forth front top to bottom and then do the same from side to side. If there is play top to bottom, then your ball joints are going or already are bad. If there is movement in all directions, then the unit bearings are toast and need to be replaced.

Start looking for worn bushings in all the steering linkage and leakage around the steering stabilizer, if you have one.

After that, I'd have the tires removed from the wheels and get them checked for out of round or ovaled lug holes.

Driveshafts can be out of balance, but unless you hit them on something, they would tend to be that way from the get go.

 

I had the same problem, started subtedly, but then got real bad. Also happened to my brother in laws '05 3500 DRW. Both of us had our driveshafts replaced. The cause was the driveshaft threw the weight and was unbalancedanduntil we got it to the dealer the carrier bearing went bad as well. All was covered under warranty minus the deductible.