2004 WJ 4.7L low freq vibe normal?

Hm... I hadn't considered that because the Wrangler ST's on it are so much less truck-ish looking than my ZJ's plain old Wranglers. Tires would make this kind of vibration worse when under the light acceleration or deceleration load?

The ones on this Jeep are ST's, not RT/S's which have a 8 out of 10 for quiet ride:

Whether or not that this about of vibe it related to the slop in the output bearing of the t-case, I still have a feeling that it is in the front driveshaft area. This is partly due to the amount of energy in this very low freq / fairly high displacement vibration. The vibrations are a bit annoying to the bottoms of my feet... glad I am not ticklish! Actually, it feels a lot like an old pickup truck that I often had to drive that had totally worn out U-joints on it, just not that intense. That's why I got under it and shook the prop shafts - something that I did from time to time on my ZJ.

All kidding aside, your comment has got me thinking about something I once read about adding dither noise (dither vibrations). This is the idea of adding more overall vibrations, just detuned (i.e. white noise) as opposed to a particular frequency. This is somewhat like the changes made to tires a long time ago when the manufacturers went to a tread design that didn't have the same size tread widths all the way around the shoulder. Even though this example actually reduced noise overall, maybe I can play on the same theme by adding pseudo-random vibrations with a noisier tread.

I have been told by a DCX mechanic that they went back and forth between cardin and U joints a few times throughout the WJ's. I am now curious as to why and when! I think that before I drive another new WJ next week, I'll get under a few and see if the slop is present in those NV247's as well.

God Bless America, ßill O|||||||O> mailto: snipped-for-privacy@aol.com

-- Russ Panneton snipped-for-privacy@hotmail.com Nederland, CO "Too bad ignorance isn't painful"

Good question Russ. As planned, I went back to the dealership and went out for a ride in another new WJ with the service manager who informed me that everything was in spec. I was unhappy to find that this WJ had the vibration between 70 and 85 mph as well, but clearly less pronounced. I then put both that WJ and my WJ in neutral and shook the front driveshafts where they exit the t-case and we both agreed that there was more slop in mine by a small amount. He informed me that even so, mine was in spec and as such could not be submitted for a warranty claim. He wants me to drive it for another 7000 miles and see what develops. I find it interesting that DCX would take the "jeep" out of the Grand Cherokee for next year to make it more car-like when they still buy sloppy components from suppliers like New Process Gear (or whatever company/component is causing this vibe). If jeeps become just another SUV that is car-like, DCX will now have to compete with so many vehicles, some of which are far more refined. It will be interesting to see if the critics of the new jeep on this NG are correct. As for me, I'll give it a year or two to either do something to it that helps it or trade out of Jeep forever. Man, I wish that I kept my ZJ!