NM-XJ

Howdy folks,

Just finished installing new U Joints in the front axle and drive shaft. Also installed new pads and rotors while I was at it.

Did a "shakedown" run today and noticed a new vibration between 55mph and 57mph. Very mellow - not death wobble - at the rate of around a couple hertz. Seems to go away if I steer to the right...

On 235/75R15's, at 55mph, wheels are spinning at about 2.7 revs/second. Front drive shaft, w/ 3.07 gears, would be spinning at 8.5 revs/second. Frequency of vibration better matches the axle shaft/tire speed.

Braking seems smooth with no vibration. Any thoughts on where to look? Start with a balance and rotation?

Thanks!

Jooman07

Have you gotten any fast to see if it comes back? Is it present while going over bumpy roads/terrain at speed?

If not then yeah I'd look at the balance and go from there. Also, do you have factory or aftermarket rims?

NM-XJ

Seems to reappear about 75ish. Present at speed regardless of terrain, most noticeable on smooth pavement.

Balanced and rotated - still happening. Factory rims, stock ride height Up Country package.

While rebuilding the front, I accidentally washed away my match marks on the transfer case side of the front drive shaft with parts cleaner. If I installed the shaft 180 degrees off, could that cause the problem?

Jooman07

Not sure if it could or not. The driveshaft may be out of balance however. Not sure how you'd balance it though.

NM-XJ

I'm skeptical of it being out of balance. There was no vibration before I did the work, and all I did was replace the U Joints and ball centering yoke.

Frankly, I suspect many people would never even notice the vibration. So mebbe remember it's a Jeep and keep rollin?