2005 LJ drivline vibrations

[2005LJU]

2005 LJ auto. 33" tires, OME ultimate kit from Dirk (2.5 coil lift, 1.25 body lift and motor mount lift). Re-geared with Revolution 4.88 gear.

Been driving it nearly 7K miles with no issues. Today i started to develop a driveline vibration at 65-70MPH..goes away below 60. A deep bass like hum and some vibration that I can feel on the floorboard.

Got home and pulled the front driveshaft...took a test drive up to speed and no vibration. Great..so its something in the front..maybe. Ujoint is new at the pinion and from what I can tell, the driveshaft angle is pretty dang near spot on...plus its an LJ with a small lift. I dont have adjustable control arms...yet...didnt think I really needed them. The double cardan joint is original 2005 vintage. What's the chances that this could be the culprit and has started to fail due to the increased DS speeds after the re-gear?

Also, I don't see where the DS has thrown a weight off or anything.

Thoughts?

Thank you.

 

[2005LJU]

Nothing?

 

[TimV]

Well, I'll share my recent experience, it may be helpful.
The front ds on my LJ started doing the squeak with each revolution last summer. I sprayed fluid film on each joint several days in a row with a week between joints, if I'm making sense. The idea being to give time for penetration and see if the squeak goes away. It's was the double cardan. As things go, I was at the driveline shop for an unrelated matter, and they would refresh the ds for 150 bucks. No brainner as parts are same cost.
The shop called back, told me the double cardan was completely shot and should be replaced, the spline section was near limits of play, and the single joint had been hammered within an inch of its life. Thank-you PO. So, complete new driveshaft. Smooth as glass now.

So, all that blathering is to say: maybe your shaft is just plumb wore out.

Good luck
Tim

 

[Jerry Bransford]

I'd sure be most suspicious that the DC (double-cardan) joint is the problem. How does it feel when moving it around? Tight and smooth to move or loose and sloppy-feeling?

 

[2005LJU]

I'd sure be most suspicious that the DC (double-cardan) joint is the problem. How does it feel when moving it around? Tight and smooth to move or loose and sloppy-feeling?

Thanks for the replies. I haven't had a chance to check that yet. I simply disconnected the front DS at the pinon and zip tied it to the frame for test drive. I'm assuming that I need to pull the entire driveshaft to check the joint...is that correct?

 

[Jerry Bransford]

Thanks for the replies. I haven't had a chance to check that yet. I simply disconnected the front DS at the pinon and zip tied it to the frame for test drive. I'm assuming that I need to pull the entire driveshaft to check the joint...is that correct?

Yes.