Every since I have had the 2007 5.9 3500, it has had a vibration over 70 MPH. It seems to be worse on some highway types (concrete, grooved payment, asphalt, etc) than others. It has also developed it's 3rd pinion seal leak in 27000 miles. Could these leaks and the over 70 vibration be coming from a U-joint, unbalanced driveline, cardigan joint, etc? The dealer says the vibration is tire related (B F Goodrich 285's) and will go away once the tires are worn out and replaced. I have a very good dealer, but I do believe they are missing this one. Also, does anyone have the TSB # on the G56 leaks on the shift tower (damage at plant from fork lift)? When I have the hood up you can see fluid on top of the transmission. Sorry for the long post, just need help.

 

Anyone with any ideas. All help would be appreciated.

 

Continuing Pinion seal leak is from job not being diagnoised adequatelly. Perhaps there is a burr on yoke that cuts seal. Perhaps the seal is being wraped during installation by not using correct install tool.
3500's are rough riding units that respond to various inputs significantlly. Such as tar strips. Does it ride smooth occasionally on some sections of highways? If this is correct, then tire balance, runout and or radial load runout are perhps not the issue. Aftermarket oversized tires are a familiar source of vibrations issues. Oh, yes 3500's require a load to ride smooth and handle road roughness inputs that upset ride. Dodge's theory is pay the extra money for a 3500 means you are serious about hauling a load. A 1500 is not nearly as unloaded sensitive.

 

I've had 2 other 3500's and they didn't do the vibration at 70. The tires may be load sensitive as the dealer has suggested. I don't believe this is the old problem that everyone used to complain about on the 03-05's of the 70 MPH vibe though. Doesn't feel the same. I was wandering if the pinion seal could be reocurring because there is a bad u joint or something on the drive shaft causing a slight vibration thus wearing on the pinion seal. Thanks