drivetrain vibration when warm?

[aaronck]

Hi all
I'm noticing a vibration in my drivetrain, but only after I've been driving for a while.  It seems if I hit over 100kmph  I get a little vibration, and when I'm driving after that, my drivetrain seems to get a little clunky.  Regular driving seems to be totally fine.  I don't get on the deerfoot much, but I did today and totally noticed it.
I have a stock 03TJ

[BlackYJ]

It kind of sounds like it is speed related, so when was the last time you had your tires balanced?

[Evil-Jeep]

A couple possibilities for you:

If the vehicle wanders or drifts on the road then, it is more than likely warn suspension or steering linkage or alignment.

If it holds the road in a nice straight line then check to see if your tires are properly balanced or have any odd wear spots, also could be a driveshaft that has been bent or dented.

Another posibility, though it is less likely could be loose body pannels or exterior pieces that are "shuddering" with the added wind resistance at higher speeds.

[Immortal]

U-joints?
Don't they shudder under load? anyone?

[aaronck]

I assume it's connected, but the highway shudder is one thing, but after driving around for a while, highway or not, my drivetrain seems to clunk a little, and maybe vibrate as well...do U joints heat up and then then get sloppy?

[RUBI]

Crawl underneath and have someone rock ur Jeep.....if there is any play in the U-Joints you will see it at the bearing cap ends.
 And yes they will be sloppier when warm !!!

[BlackYJ]

If it shudders all the time then i would look at all your suspension joints and trackbar joints for worn parts

[aaronck]

Ujoints are all tight, I'm convinced it's something in the drivetrain, so I booked an appointment at the dealership.
It's an 03 TJ with 72,000 on it, what sort of warranty do I have left?  What's the difference between powertrain and regular warr?

[aaronck]

Long time no update-took it into the dealer and they took it for a test drive-but not long enough for it to heat up and start the grinding.  I knew my power train warranty was up end of April so I took a day off to take the Jeep out for a long enough drive to get it grinding and then took it into Tower.  Shop Forman took it for a spin-noticed the grinding (not the worst I've heard it, but noticeable) and suggested perhaps the fluid was no good and recommended a Diff oil change and new additive be put in, as it sounded like the Posi clutches were not working properly when the fluid heated up.  just got a call from the dealer-Posi is toast-new one on order and being installed under warranty with about 2 weeks to spare! 

[aaronck]

spoke too soon....Tower is saying that it has a Posi rear end and there's not supposed to be Posi there, so they're treating it like an aftermarket mod and saying it will not be covered, and that they want $1800 to replace it.  I'm 99% sure the 25 year old girl I purchased it off wouldn't have modified it, as not only was it not off road, she hadn't even put on the soft top for the 3 years she owned it.  I'm panicked-anyone have any ideas?

[w squared]

If it's a stock posi, then it should be covered under warranty, regardless of what's "supposed" to be there.

Unles Tower thinks that the Posi gremlins snuck under your Jeep at night and installed one. 

[aaronck]

thanks for the superfast answer!

I called the girl's mom, and she's also 99% sure nothing was ever modded.  I assume it's the factory Posi, they seem to just know that the part they ordered doesn't fit, so I should pay $1800

Is Tower a decent dealership?  I know they used to sponser the CJA

[aaronck]

Still in limbo with this.  Chyslers position is that the Diff is a Posi diff, and based on the serial # and even the window sticker-it is not supposed to be a posi, meaning it was a factory mistake.  So I would have a vehicle they re-assembled and filled the Dif up for me-and when I went to pick it up they had a $350 bill for me, for not fixing anything?  I left without having to pay, for once everyone being busy  and not able to talk to me works to my advantage!
Hopefully will hear today an answer from Chysler and get the thing fixed up once and for all