ZJ tech, please help, REALLY stumped

[summitlt]

Ok, moms truck, 1996 Grand cherokee, 4.0, NV242

This is REALLY weird, sometimes, (not all the time) the front driversside "wheel" makes a hellacious noise. Like a wheelbearing that is COMPLETELY gone, were taling grinding, popping and noises that you dont want to hear. You can feel it in the floor and if your going by a brick builing you can hear it echo off them.

Heres the thing, after about 15mph, it goes away completely, below 2 mph it doesnt do it. If you ride the brakes (ever so slightly) its silent. It only does it sometimes, you cant make it do it.

I have touched and banged and tried to move everyting under the truck, nothing seems to be loose at ALL.

If I jack the front wheels up (one at a time) and use the fulltime 4wd, i can spin one tire, it wont make the noise no matter what I do. If I turn the wheel to lock though it makes a sorta similar noise and the whole drivetrain kinda bucks, like somethings binding. Only at close to and full lock. Which a loud clanking sound out of the Tcase. The sound it usually makes is NOT the tcase. I am at a standstill, I dont know what it can possibly be, I kind athink U joints, but its random when it hapens and it doesnt matter if its in 4wd or not. I think wheelbearings, but its random, last I knew wheelbearings and u joints dont fix themselves.

Any ideas?

 

[DrMoab]

Look and see if it has CV joints instead of Ujoints in the axles. I cant remember if the 242 equiped ones do or not.

Anyway if it does it could have a bad joint. Maybe a ball rolling around in there that only catches once in awhile??? I dunno...just a thought.

 

[summitlt]

theyre u joints, regular old everyday d30

 

[johnnyc]

I say wheel bearing/hub assemblies.

Those are the same symptoms I had the first time mine went bad. Didn't notice anything at higher speeds. Only at low speeds. And braking will make the noise go away because the caliper is "straightening" the wheels up.

Does the noise and grinding occur when turning at slow speeds?

 

[summitlt]

It does do it while turning, a little worse than going in a straight line. Up hill and turning seems to be the worst,

 

[nitejohn]

It's your axle U joint. I have a 96 zj 242, same as yours, and had the same problem. It cost me $16 for a new one, but took a hell of a lot of work getting the unit bearing out to pull the axle shaft. the 3 12 point bolts holding it in stripped from rust or whatever, and i had to dehead them to finish the repair. that was another $6 for hardened replacement bolts from my local hardware store. probably more than you wanted to know, but being your from Maine and it's 11 years old, you might run into the same problem with your fix. Soak everything with pb blaster for a week before you try to take them out. good luck

 

[Bryan C.]

If you ride the brakes (ever so slightly) its silent.

Any ideas?

Yeah I do. I am a dealership mechanic with over 10 years working on Jeeps. I have seen this before. Seems like this vehicle has some cheap front brake pads on it. Have they been changed recently? Usually that is the case, even if the haven't been replaced recently it is still the same issue. Go get some high quality brake pads and resurface or replace the rotors. While you got the calipers off, take a look at the knuckles where the pads contact, if there are grooves from the pads then you will need some new knuckles too. The fact that you can ride the brakes and it goes away should be a hint as to what the problem is.

 

[summitlt]

Uh, it started soon after I did the front brakes on it....

Hmm, theyre carquest blues i belive.

Whats exactly is making the noise though? theres grooves in the knuckle, is it the pads riduing around on those grooves?

 

[Bryan C.]

Uh, it started soon after I did the front brakes on it....

Hmm, theyre carquest blues i belive.

Whats exactly is making the noise though? theres grooves in the knuckle, is it the pads riduing around on those grooves?

It has a little to do with the grooves, but mostly it is the pads. For some reason the ZJs are really picky about what pads they have on them. I know you don't want to hear this, but go and buy a set from the dealer. Tell them you want a set of the v-line pads for your Jeep. The regular ones they will try to sell you are way too expensive, but the "value-line" pads will work just fine. You can try to relieve the edges og the grooves a little with something like a dremel tool, but I would suggest trying another set of pads and smoothing the out the grooves before replacing the knuckles.

 

[jneary]

there are left and righ pads, are you sure you put them on the right sides. also check the spindles to see if they arent grooved from the old pads rubbing them for years

 

[neonrog]

I never buy buy "cheap" brake pads. ALWAYS name brand, and never bottom line. I'm going to be replacing my rotors and pads on my ZJ soon, and am really thinking about powerslot rotors and EBC pads.

My F150 Supercrew rides with ceramic pads and I reall ylike how they stop that truck when I pull a trailer. Lack of brake dust is nice too!