I get a droaning/loud vibration in my floor at highway speeds (65+). It's more or less a pulsating vibe and it's quite loud. Only happens when I'm on the gas at hwy speed. When I let off the gas it stops. Its a 2000 xj classic 4x4. I have a full 3" zone lift and I just replaced all ball joints, brand new timken front hubs, new axle u joints and both rear drive shaft u joints. Also have new 31" m/t tires that I've had balanced twice and an alignment twice (because I was convinced it was alignment or tires). Wheels are also brand new.... I have all new bushings up front and new lca's as well.

What am I dealing with here???? Need some seriously quick help before I take myself to the looney bin....

 

No one????

 

Alright I'll make this interesting... $5 paypal to the first person to diagnose this vibration successfully...

 

Might just be slow this early in the morning. Anyway, it sounds like you've narrowed it down to the front but those kinds of sounds/vibes can resonate. Your best bet would probably be to get the wheels off the ground (with other wheels chocked) and get them spinning. Watch the driveshafts for any wobble or listen for the vibration from underneath the vehicle. I'm experiencing the same thing, so I'm subscribed to this thread. One thing that was recommended to me was to check my transfer case output shafts. At one point my front driveshaft was so long it may have bent my TC shaft in the front when I compressed my suspension. The seal is supposed to leak if that's the case though... Definitely a problematic vibration; the type that'll shake bolts loose.

 

Pull the front DS and see if that helps. Mine made all kinds of noise before the double cardigan joint failed.

 

Do you have a roof rack with a spare on top? My 2000 XJ groans at 65+ (coming from straps)

 

Just an update...... Per suggestions above I will be checking both drive shafts as well as my trans case for play/wear. Will update again tomorrow after my testing...

 

My '99 vibrated with a 2" lift until I dropped the transfer case an inch. The vibes are gone now. I think with a 2000 and 3" lift, you could use a SYE or a transfer case drop.

 

^ I have a trans case drop already. May be time for an Sye.. Will see. I'll be wrenching away tonight.

Would it make sense that my front shaft was making these vibes? I have extended lca's and stock uca's and I feel like my front axle angles are kinda whacky now... Maybe those angles are making the front shaft vibe at higher speeds?

 

Double Cardigan:






Double Cardan:

 

^ HAHAHA

 

Lol

 

late model XJ's are finicky with front DS angles. it might be that.

 

The late model rear xfer case output was longer, making the rear shaft sensitive to driveline angles, not the front. I've got early model junkyard spares that match my late model in length as well as 6" of lift on the front OEM shaft with no problems.

 

^turns out the front was the majority of the problem. I do still have some vibes from my rear, but the slip yoke up front had a lot of up and down movement and when I took it out it eliminated a lot of the bad vibes. I need to figure out the best fix for the front shaft now and also probably get an sye for the rear to totally eliminate the vibes.