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variable 03-18-2015 05:08 PM

93 ZJ V8 Dana 30 pumpkin bearings... all of them
Hi all, been a long time since I've had a jeep to play with and I'm glad to be back. A little older, a little wiser (I hope), growing hair in strange places... (Waynes World 2 fans out there?)

Okay, I'll get to it.

Short story long, bought a 93 ZJ with a lot of problems (basically got ripped off because, well, I'm an idiot - so I guess I didn't get ripped off, I'm just an idiot :rolleyes:)

Its got a pretty gnarly grinding noise coming from the front end and I was given to believe that it was the wheel bearings - easy enough to replace on that guy, though before picking up parts, I noticed the right CV boot was pretty much gone so I just went to town and replaced the hubs and half shafts on both sides, figured I'm going to have it apart, I might as well.

Not the wheel bearings.

So... my GF's Dad's friend (think I got that right) restores Cobras (out of his house...) and graciously offered to let me use his lift and tools, but I don't think any of us has ever done any real diff work (I've changed the fluids...)

So, to get to the point, I've been poking around and I see a variety of kits and pieces and I'm trying to figure out what all I need. I'm going under the assumption (I know, assume...) that the carrier, the ring gear and pinion gear are all in working order and don't need replacing. I'm also just going to go ahead and assume that the carrier and pinion bearings are all toast (might as well if I've got the tools...) From the various youtube videos I've watched, what I gather I need is the following:
  1. Carrier bearings & races for both sides of carrier (the kits all seem to come with the races)
  2. Pinion bearings - looks like there's an inside and an outside bearing
  3. Pinion nut (is this one of those suggested replacements?)
  4. Oil seals
  5. A crush washer? Briefly mentioned here and there.
  6. Dial indicator - for checking lashing
  7. Shims
  8. Ring Gear paint
  9. A ginormous torque wrench
  10. Diff cover gasket
  11. Bearing puller
  12. Bearing press

So, I guess the question I have is, am I missing anything? Do the oil seals need anything special for installation/removal? My subaru apparently needed a special tool for it. There seems to be a lot of threads, posts, googlage about different portions of the job, but I haven't really found a good write up on the whole spiel.

Also came across a couple of kits that were for a short pinion diff and I'm unclear what thats referring to.


If there's already a good write up for this, could someone point me in the right direction (and I shall bow to your search-foo :cheers2:)

HighLonesome 03-19-2015 07:47 AM

Normal kit.

Never done the oil seals but yes there is a Mopar special tool for the job. It is shown in the FSM. But they can be replaced without it.

variable 03-19-2015 09:48 AM

Thanks :) If/when I get the chance to actually do it, I'll try and post some pics.

Now on to yet another case of rough idling and vacuum gremlins...

MoparmanNJ 03-19-2015 10:03 PM

Was it a constant grinding or an intermitent grinding?????

MoparmanNJ 03-20-2015 08:38 AM

I have the same story. Only i didnt buy the jeep yet. Is there a way to tell if its wheel bearings or a differencial?

HighLonesome 03-20-2015 10:19 AM

You could mistake a bad wheel bearing for a very bad tire(s).

variable 03-20-2015 11:03 AM


Originally Posted by MoparmanNJ (Post 29027417)
I have the same story. Only i didnt buy the jeep yet. Is there a way to tell if its wheel bearings or a differencial?

I guess it depends how loud it is and at what speed you start noticing... a directional microphone while chasing the jeep?

In theory, if the wheel bearings are bad, the noise should get louder when you turn. If its just the diff, it should make noise either way. As for telling whether or not its the carrier or the pinion... jack stands, a stethoscope and a brave friend?

MoparmanNJ 03-20-2015 12:14 PM

I think it was straight and turning. I didnt drive it long. Gas light was on. It wasnt a high pitch bearing noise. It was more of a grinding. Also the pinion seal was leaking. Could i check for play in the front drive shaft or jack up a wheel and rotate a tire? This jeep is in great shape. Just little problems and high mileage. Looks like its had an easy life though. Drivers side leather seat is flawless. They only want 1000 for the jeep.

variable 03-20-2015 12:29 PM

Well, think of it this way, if anything has play in it (not counting wheel bearings - though that would be bad too), then that would mean that the pinon gear and ring gear could potentially be moving in such a way as to allow them to jump gear teeth, or more likely for bits to start coming apart (or worse, cause the whole damn thing to explode from binding and who knows what). I would venture a guess that you won't find any play that you could measure with your hand, save maybe some play in the u-joints - a different problem entirely.

It doesn't sound like there's an easy test without getting under the vehicle and/or putting it on stands. In my case, the sound is pervasive enough that I can't tell where specifically its coming from, I'm just using deductive reasoning since the wheel bearings and half shafts are brand new. However, I haven't put the whole thing up on stands to see if I can narrow it down (I should..)

MoparmanNJ 03-20-2015 07:51 PM

I found a video that sounded exactly like i heard. Found a video of a jeep with a bad cv joint. Not turning the wheel while driving. Lots of grinding sounds. Pretty sure thats what ill find. Im going back to check out the jeep tomorrow and look.

mudwaller88 03-20-2015 08:12 PM

I would also check your double cardan joint at the tcase on the front driveshaft. I thought I had bad carrier bearings or wheel bearings, it turned it to be the double cardan was completly wasted

variable 03-24-2015 10:36 AM


Originally Posted by mudwaller88 (Post 29041857)
I would also check your double cardan joint at the tcase on the front driveshaft. I thought I had bad carrier bearings or wheel bearings, it turned it to be the double cardan was completly wasted

I hadn't considered this, though quick visual inspection didn't reveal anything - they seem OK, no play that I can see, though I didn't actually pull them off and inspect them. Was it pretty obvious on yours that they were toast or did you just pull them for good measure?

I pulled the cover off the front diff last night - got started late and I wasn't thinking far enough ahead and forgot that I had wanted to get all 4 off the ground so I could run it in mid air and listen. Anyway, looking inside my diff revealed nothing aside from a very dark colored gear oil... No metal shavings though - which I was expecting to see - and no play or shaking/rattling and from what little I could see, the bearings *looked* ok, but again, I only popped the cover off.

So I put it back together, filled it up with 75-90 and unsurprisingly the noise was still there (wasn't expecting much).

I recorded some of the sound, ran it through some filters which will hopefully bring it out a bit. Keep in mind - its got new tires, new halfshafts/CV's, and new wheel bearings (and now new fluids). Youtube wasn't cooperating so I stuck it in a dropbox link (hopefully this won't crap out) - they're in mp3 format:
1 -
2 -

I'm going to try and get go at it again tonight and see if I can isolate it more.

The time now is 11:51 AM.

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