1700 rpm buzz/vibe

[realfine409]

Need some input!! Bought a used 07. 5 6. 7 w/ 68rfe with 88k. Shortly after the purchase I noticed a pretty pronounced vibration between 1600 and 1800 rpm (68-72 mph). Took the single piece rear driveshaft to a local drive line house, he showed me the bow in the middle and the too nermerous wieghts that he said was a bad sign. SOOOO! $300 bucks later have a very straight tube w/ new spicers, now it's less but still there. Took the front driveshaft off, most of it went away. Looked at the tranfer case flange, maybe . 015-. 020" of radial movment. Looked at the axle pinion flange, less than . 015". Replaced all of the u-joints w/ Spicers, replaced the cardan sphere and seal, just put it in, took it for a test drive before replacing the rock guard, still there! It's a fast enough frequency that it almost sounds and feels like a buzz at 70 mph, then goes more into a pronounced vibration and the buzz dies off when slowing to 60-65. I was carefull to place witness marks on all of the pieces and flanges so I'm pretty sure everything is in phase. I have a bunch of trips planned this summer (Columbus IN for one!) and don't want to burn up everything in the drive line with this discomforting vibe. I have researched the archieves but did not find anything similar other than the usual. Any thought would be much appreciated.

 

[realfine409]

Ok, I jacked up both sides again today, spun the drivers side wheel while looking down at the axle UJ. If I rotate forward and quickly reverse the tire, definite clunk and slop in the UJ. As I don't have a lift, compressor, or big ***** tools I'm taking it to a shop for the replacement. So far quotes range from $250 to $500 for one side. I've read somewhere here that it's possible to damage the interior seal on AAM axles. Any way to minimize that possibility on reassembly? Also, should go ahead and replace the hub bearing while this far?

 

[Bob4x4]

The 9. 25 axle seals have a hard plastic tapered guide to help protect the seal when the axle is reinstalled. I personally have not had any leak after repairing or replacing an axle. Of all the front end work I have performed on the 9. 25 I can only recall replacing axle seals on one truck

 

[realfine409]

Thanx Bob, that reduces my paranoia considerably. I had 1 shop preface thier quote (lowest) with the disclaimer that they have experienced this issue before (groan) and they wouldn't be responsible if it happened. I think I'll pass on that shop.



Thanx Again,

Roger

 

[RVTRKN]

If your front axle u-joints are worn, I'd recommend going to dynatrac, or equivalent, here is a link.

http://www.dynatrac.com/products/freespin-dodge/freespin-dodge.html

 

[realfine409]

Vibe and Buzz is gone! Replaced both axle joints and bearing hubs. Smooth and quiet, ready for some road trips this summer!!

 

[HBarlow]

Congratulations on good mechanical detective work. We've had several members show up here reporting vibration issues and I don't know if they were ever resolved. You solved yours and the information shared might help another member sometime in the future.

 

[realfine409]

I'm at 100,500 miles, replaced the OE's w/ Spicer and Timken. This will be a good benchmark in terms of durability without severe duty as it's parked most of the time and used to tow the 5er, with little to no off road use. Still I want to 4x4 it sooner or later, possible at the outer banks this summer. Thanx for everyone's input.