My '99 Cherokee has suddenly stayed having a front end vibration and growl at highway speeds (anything above about 45). Any ideas?

 

Some of the first things I would check.

Fluid level in the front differential.

Jack up one front wheel at a time, and check the wheel bearing for play. Try and rock the wheel top to bottom and see if it’s even a little bit loose.

While the front wheel is jacked up, spin it and watch the u joint for play. There should be no visible play.

 

after you got done what the 1st guy said, if nothing obvious, get under the front with it jacked up, using prybars, or a jack apply pressure to each ball joint, tie rod, pitman arm etc, and see if there is any "freeplay"

 

Thanks, guys. I'll def check it out!!

 

My son and I did all of theses checks. Looked at transfer case lube as well. All were OK. Any more ideas?

 

Its either going to be a bearing or u joint. Could be either of the wheel bearings, axle u joints, drive shaft u joints, or bearings inside the diff.

Remove your front driveshaft and go test drive. If howl is still there, you have eliminated the driveshaft u joints from the equation. You also should be able to feel if the u joints are gritty while its off.

If that checks out, inspect wheel bearings next. Remove wheels and brakes and rotate the wheel bearings. They also should not feel gritty. This might be hard to get a good feeling for while everything is installed. It will be easier to do if you remove the bearing and axle shaft. This will also be a good opportunity to feel for grittiness in the axle shaft u joints and change out your diff fluid while inspecting inside the diff. If the fluid in the diff looks rough (muddy/milky/metallic) then that points to a carrier or pinion bearing issue.

Have you made any changes to your suspension/drivetrain/alignment recently?

 

at least swap wheels/tyres back to front, as a slight issue can result in a vibration

I had my XJ 99% cured of any vibration, and the final piece of the puzzle was changing to alloy wheels (and good quality tyres), all second hand

The trackbar and draglink were changed out, (and some other parts)

Unfortunately it never ends, I ended up replacing the entire D30 assembly, after swapping all parts, mystery grinding noise, all good for another year

now it has a slight woomp woomp sound... and vibration....as they get worse, one can hopefully diagnose the issue

One thing I havent done is rebuild the front driveshaft, it has a cardan joint that eventually goes bad, and 2 u-joints, I will be removing it for a test myself

 

sticking calipers? check the temp