Rear Diff Noise! Help?!

  I've got a noise going on that sounds somewhat similar to the beginnings of a U-joint starting to go.  But it's not a U-joint!  I've narrowed down to the rear diff.  (Stock 44)

  Here's what I've got.....

ON THE ROAD...The said noise is heard louder with more torque being provided.  It's louder in turns than opposed to going straight.  It's louder in 2WD as opposed to 4WD.

IN THE GARAGE...Rear end is raised, Driveline is disconnected, Diff cover is removed.  The siad noise is heard about 8 times per tire revolution and about 5 times per yoke revolution.  It's heard easier when one tire is held still and the other is spun.  

THEREFORE...It is easier heard when there is a greater differentiating torque to the opposing sides of the diff.

 I HOPE THE ASSUMPTIONS OF MY FINDINGS WILL BE NARROWED AND CONFIRMED.  BBFF is coming up and I need to ride a few times before it.  

I am assuming there were no metal bits in the oil when you removed the diff cover?
The pinion nut is tight and there is no slop in the pinion bearings?
Are all the ring gear teeth intact?
Differential teeth?
Pinion teeth?

It sounds like the differential gears. But without bits of metal in the oil I'm a little baffled.

If all the gears look good and there is no metal in the oil I would pull the axle shafts and inspect the bearings. If you find nothing out of the ordinary, pull the carrier and inspect the bearings here too.

If the gears are all good I'd put my money on the carrier or axle bearings.  

You're correct...Fluid good,no slop, teeth in good shape, good markings of contact...

I first thought axle bearings, but the sound is the same and equal on each side of the axle with no slop or grinding.

Then I thought the bearing for the yoke, but that seems good on closer inspection.

Similar to you, I'm leaning towards the carrier bearings.  (but as of right now, not the axle bearings)

On another note, I'm figuring there may be som play in the pivoting of the smaller planetary gears.

Is pulling the carrier as simple as pulling back the axles a few inches and unbolting the bearing retainer bolts.  

Yes, but mark caps before you yank it. The bearing caps need to go on the same way and on the same side that they came off of. And the bolts need to be torqued properly when reinstalled. The carrier usually needs to be pried out.

But before you do that try this: With the Jeep on jackstands. Reinstall the rear driveshaft, put the Jeep in park (auto tranny) or First gear (manual tranny), put the t-case in 2WD. Then spin one of the rear wheels (driveshaft should not spin!). The other tire should spin in the opposite direction. Is the noise still there? If so it is not the carrier bearings. It is in the differential itself or axle bearings.  

Thankd for the quick replies!!!

OK!  Rear drivelin back in position, 1st gear engaged with 2WD active.  Spun on trire, the other does spin the opposite direction as expected.  As for the noise?!  Still there.  So, your sayig in this case, it's the diff or the axle bearings.

Can the axle bearings be negated do to the similarity of the noise being heard somewhat evenly through out the rear axle?

Anoter note:  How much play is expected in the diff itself between its main bearings on each side?  I just noticed about 1/8 of an inch.  Is that do-able?  Also, the noise seems to match the teeth of the smaller planetry gears as they rotate.  Hummm?!

I sure would hope to be the axle bearing(s). Less cost!  

OH!  I also noticed that the diff itself was able to be wiggled by my hand inside of the two main bearings of the diff.  If a had to guess, I'd say just a couple of degrees against the axis.  

It sounds like there may be a couple things going on. The carrier bearings are shot if you can wiggle the carrier side to side. I suspect the carrier is shot too if the diff gears are that loose. Have you been stuck with only one rear tire spinning often. That'll chew up the diff. As for the carrier bearings, they can go, especially if the TJ Dana 44 bends. Sounds like you really need to pull it apart.  

Thanks again.  i did tinker with it a couple hours ago.  I confirmed the carrier bearings are shot.  I'm figuring (hoping) the carrier is ok for now (until I can lock and regear it).  I think the looseness that I saw earlier was disguising the carrier bearings.  With the driveline in place along with 1st gear and 2WD engaged I'm able to see a clearer picture of what's going on.  Thanks again!!!

As for "stucking it" and spinning one tire, I keep everything in control especially that I'm not locked.  [Well it did see soem heavy torque three weeks ago on Dishpan when it almost flipped, or was it John Bull?!]  It does have over 230,000 miles on it and engine still puts out.  My wife  bought it with about 212,000, who knows what the previous owners son did with it.  I know he jacked up the bell housing bolts when he ATTEMPTED to replace the clutch. (I correspionded with you on that last Easter)  Thanks for that help too!!!

I'll try to pull it tomorrow and follow up.  

OK Y'all!  Here it is!  What I've got is a case of Bearing Boggle-itis.

The carrier bearings are shot.  Well, not completely shot.  Thankfully, i took the jeep off the road to find the problem before things got eaten up by any metal shards that would have loved to manifest into the beauitfully good look teeth of the planetary gears.

Thanks for the help!!!  Tinkering alone, I would've figured it out, but the re-assuring info by you helped lead the way a bit quicker. Plus, the help from good 'ole Sam Adams provided the lube needed for such a project.

I've ordered the parts from a well-known 4-wheel parts place here in Temecula.  The DM said they'd be in my hands tomorrow. Alot better than the local generic parts place.

Oh, by the way, when at the local parts place, the shmuck running the counter, upon coming the the choices for axle regarding my part, he saw, "Dana/Spicer 44" and "Dana/Spicer 35" on the computer screen.  He then proceeded to ask me, "How many splines?"  I then had to clarify with him what he thought the "44" and "35" meant to him.  He was a bit off.  I found myself teaching him the basics of his job.  It wasn't the first time, nor will it be the last, I'm sure.  Can we say Autoidiot?!  Sorry for the jab, but impressions follow!  They still can't find the right whell-joint for me.  I've had to go into the back supply myself to find it.

Being quite mechanincal, I've never busted into and tore apart a diff like this.  I'm taking the precautions I believe are neccessary.  Any notes fromt he jury before I start throwing it all back together?  

Make sure the shims behind the bearings don't get re-arranged or removed accidentally by whom ever is removing and pressing the bearings.

The shims should be correct for the new bearings. They usually only change for gear and carrier changes.

Install bearing caps in original position, torque to 57lbs. and measure your ring gear backlash with a dial indicator from at least three different positions.

It should be between 0.004 - 0.009 and not vary more than 0.002 from any of the three measurments. You have to pry the carrier from side to side to take these measurements. Zero out on one side, pry the case over and take the measurement.

This is just to make sure nothing got damaged and everything is back to within spec. If nothing got damaged the backlash shouldn't be affected by the carrier bearing change.  

Correction to my above post:

You have to pry the carrier from side to side to ADJUST these measurements. Zero out on one side, pry the case over and take the measurement. (This determines shim pack thickness)

For backlash measurement:

The plunger of the dial indicator is set against the ring gear tooth, rotate the ring gear until tight against the pinion tooth, zero the dial indicator, then rotate the ring gear in opposite direction. This is your backlash measurement.

It might also be a good idea to put some marking compound (yellow oxide) on the ring gear and do a test pattern.  

I'm assuming, as well as you are that the shim packs ought to be fine.

Would the backlash be adjusted by the shims as well?  (i.e.-certain thickness of shim correction on each side)

as i said earlier, I've never had a dif in my hands so... where would the shims go?  I don't see any on the one I pulled out. Or do I?!  

The shims on both sides total the measurement needed to take up carrier end play.

To adjust backlash, shims are moved from one side to the other, but the total measurement of all shims stays the same.

I think this is important because of the amount of end play that you described. That much end play could have caused excessive wear to the gears and/or the pinion bearing.

Taking these steps would help ensure that things are OK and avoid an even worse situation.  

The amount of play that I described was (in further findingds prior to pulling it) due to slight wear in the dif housing from the left carrier bearing as well as the wear in the bearing itself.  The wear in the casing is ever so slight, so I'm hoping for the best.

With that, there is no play in the planetary gears of the dif at all (from what i see in my hand).  That part is good.

Looking at the dif in my hands, I don't see any shims, or do I? To me it'd make sense for them to be placed on the dif prior to the bearings.  Is that correct?

Thanks for your help so far. i really do appreciate it!!!  

Yes. The shims are behind the bearing. You have to pull the bearings off to get at them. You need a puller, and the new ones need pressed on.

If it has had a gear change, some install kits shim the races in the housing. So check there too. Dana always puts the shims on the carrier.

If there is any wear in the bearing, then the contact between the ring gear and the pinion could be affected. If the mesh gets too tight then the pinion bearing could suffer, or the gears could wear, or the gears will just break.

If the mesh is too loose, teeth go away.

On a side note. The differential gears (not planetary) are made up of side gears and pinion gears. The axle slides into the side gear.

When going straight, these gears are not moving. When turning, they walk around slowly. When one tire spins they run around. They're not desined for a lot of that (no bearings). This usually the only bad thing that ever happens to the differential gears.

A Planetary gear set consists of a hub with multiple gears protruding, that is installed in a case with an integral ring gear. The hub walks around the case gear.

Your transfer case has a big planetary gear set for low gear.

Anyway, hope this helps.