HELP! Identify this Dana 44 component

[jeep_boss]

I had a little sludge come out of my rear differential. When i opened the diff case, the first thing that I saw was a loose ring on the far right side nearest the axle tube / to the right of the bearing cap (that bears the stamp on the right side with the tube going in)!

I was able to push it freely back into place, but this is terrifying me.

Can anyone identify what this is and maybe clue me in on how f**ked I am?

Also notice the rust looking discoloration .. this wasn't present as far as I can remember when I did a fluid change ~3K miles ago

 

[Rob5589]

If you are talking about the silver ring to the right of the cap, that is a shim for setting up backlash and carrier pre-load. If it had backed out you may have some worn carrier bearings and/or carrier pre-load was too loose during initial set up. It should take some decent smacks with a hammer and brass drift to put it back in place.

 

[jeep_boss]

If you are talking about the silver ring to the right of the cap, that is a shim for setting up backlash and carrier pre-load. If it had backed out you may have some worn carrier bearings and/or carrier pre-load was too loose during initial set up. It should take some decent smacks with a hammer and brass drift to put it back in place.

Ok a shim makes sense to me. As far as PROPERLY getting back in place, I pushed it by hand and it sat barely snug where it seemed to belong.

That said, I'm not ready to re-gear my diff nor rebuild it yet - what is the danger in driving on it with that shim slipping down like it was? (The photo I uploaded shows it after I pushed it back up in place, but it slipped out a half inch or so)

 

[Rob5589]

It won't come out, the axle runs through it. If it keeps slipping out either the bearings are shot or there was insufficient pre-load during set up. You definitely do not want it slipping out. I would have someone experienced with differentials look at it.

 

[jeep_boss]

It won't come out, the axle runs through it. If it keeps slipping out either the bearings are shot or there was insufficient pre-load during set up. You definitely do not want it slipping out. I would have someone experienced with differentials look at it.

Looking at photos I took when I first cracked open my diff covers (shortly after I bought it) it appears that damned shim was always loose. I suppose that I was always too concentrated on the ring gears and carrier to notice.

I don't know exactly how the rust started to develop nor the source of the sludge, but here is what I know:

My ~8 o'clock diff cover bolt was loose - not even finger tight.

The breather hose was in questionable shape, not sure how it went to hell in a couple of months like it did, but I'm replacing it this evening with a new one. I'm also not sure where the end of that thing actually pops out - it disappears up near the top of my fuel tank somewhere, so it's possible stuff got in through the end.

I have no idea what the condition of my axle seals are, I don't see any oil coming out anywhere. I'm a few weeks away from getting new Revolution rear axles anyway, and I just got the tools that I need to replace them.

Beyomd that, I'm planning on swapping out my front and rear axle pinion yokes (793's) with 1310's to match up both my front 1310 DS yoke and rear 1310 CV yoke, because right now I have to use Frankenstein u-joints.

Since I'm taking care of those driveline issues once and for all, I am now seriously considering a re-build of (at least) my rear diff soon. I don't like not trust any shops in my area and I'm a fast + motivated learner. I need to be able to service my diffs on my own anyhow, so now would be just as good of a time to learn as any.

 

[jeep_boss]

I'll also add that I'm about to hit the rust with some naval jelly and then a can of brake cleaner to see if I can clean it up some.

 

[Rob5589]

Rust is from water, most likely entered through a seal or breach in the cover sealant. The breather tube allows built up pressure to escape. The tube runs up and next to the gas filler neck. You could get water in that way but it would have to be very deep.

 

[jeep_boss]

Rust is from water, most likely entered through a seal or breach in the cover sealant. The breather tube allows built up pressure to escape. The tube runs up and next to the gas filler neck. You could get water in that way but it would have to be very deep.

Could also have been caused by my power washer when I had done some deep cleaning on my Jeep's underside. I am also using Lube Lockers, not sure if that loose bolt could have also allowed moisture to enter the case.

In any case, I cleaned it up last night as best that I could with a nylon brush and a light amount of naval jelly. I'd have disassemble the diff to get the rest of it out. Replacing the breather tube this evening when I get home from work.

As far as the shim goes, I bought a 3' 5/16" brass rod and cut it down to size for smacking that guy in place. I got it in there pretty snug, but I will check it again to see if it moved Sunday evening (after my weekend camping trip where I'll be driving it ~100 miles or so).

 

[Rob5589]

Sounds good. Post a follow up when you can.

 

[jeep_boss]

It won't come out, the axle runs through it. If it keeps slipping out either the bearings are shot or there was insufficient pre-load during set up. You definitely do not want it slipping out. I would have someone experienced with differentials look at it.

Quick follow up.. I'm considering acquiring a spreader and enlisting a set of experienced eyeballs to fix this once and for all. I went to another local shop yesterday, and explained the situation to the master mechanic.

Without even opening the diff cover - his prognosis was that my bearings and pinion were both completely shot and had probably eaten the diff alive. I told him that I have been changing my diff fluids on that specific diff no more than every 1500 miles since noticing the loose shim and the little bit of surface rust. I explained to him that I wanted a quote to set the backlash and preload correctly, where he said it would be as little as $500 upwards. I thanked him for his time and walked out of the door feeling like he was trying intently to put the screws to me, which is something that I have had to donwith greedy vendors for most of my professional career - so I have come to the conclusion that the shops around here are not to be trusted, leaving me with no alternatives but to get it done myself.

 

[Jerry Bransford]

A loose carrier shim makes me think bad carrier bearing. The shim should NOT be loose, it should actually be very tight and hard to seat, and I can't think of another single reasonable reason other than a bad carrier bearing that would cause it.

A spreader is not required to get the carrier in/out. I've had mine in/out over a dozen times over the years without benefit of a case spreader. If I were you I'd go to a 4x4 shop that does axle regearings and have them tell you what's up. And keep in mind that not everyone who sees a potentially expensive problem as yours certainly could be is out to screw you. Not to mention carrier bearings that go bad and create a metallic sludge in the bottom of the case can easily take out pinion bearings. And either can eventually take out the ring & pinion gears.

 

[jeep_boss]

A loose carrier shim makes me think bad carrier bearing. The shim should NOT be loose, it should actually be very tight and hard to seat, and I can't think of another single reasonable reason other than a bad carrier bearing that would cause it.

A spreader is not required to get the carrier in/out. I've had mine in/out over a dozen times over the years without benefit of a case spreader. If I were you I'd go to a 4x4 shop that does axle regearings and have them tell you what's up. And keep in mind that not everyone who sees a potentially expensive problem as yours certainly could be is out to screw you. Not to mention carrier bearings that go bad and create a metallic sludge in the bottom of the case can easily take out pinion bearings. And either can eventually take out the ring & pinion gears.

There aren't any reputable 4x4 shops in the greater Seattle area, period. The closest I could come to one would be the Jeep dealership - any they told me that they wouldn't work on my regeared diffs.

Shops are out of the question for me period. I am not going to pay the local $150-250/hr in labor rates to fix problems that are just going to reappear down the road. It's my Jeep and I should be able to do everything to it that it needs, outside of balancing wheels (I can't justify the cost for the tools needed for wheel balancing).

Others that I have spoken with and shown photos to think this problem came about when the vehicle was regeared. It has been driven for at least 15K miles like this and has not changed (no signs of sludge beyond a little crap from black RTV before i switched to Lube Lockers).

 

[Jerry Bransford]

Yes the problem was very likely caused by it being regeared. That doesn't change what the problem is or what it'll take to fix it and what additional damage the initial problem might have also caused. From your thread the repair of this is above your pay grade so it's time to either bite the bullet and pay to have it repaired properly or sell the Jeep. Some problems simply require a whole new ring & pinion gear with all new bearings and it takes an expert to set them up properly so you won't have the same problem all over again.

 

[jeep_boss]

Yes the problem was very likely caused by it being regeared. That doesn't change what the problem is or what it'll take to fix it and what additional damage the initial problem might have also caused. From your thread the repair of this is above your pay grade so it's time to either bite the bullet and pay to have it repaired properly or sell the Jeep. Some problems simply require a whole new ring & pinion gear with all new bearings and it takes an expert to set them up properly so you won't have the same problem all over again.

I'm aware of the processes involved in rebuilding this differential, this task is not completely foreign to me. This differential is larger, but far less complicated than other differentials that I have worked on before. I'm not going to set an artificial pay grade boundary when I can get someone to help me set the depth and backlash.

I would rather buy a clamshell puller, spreader, et al - than have some greedy local mechanic fuck up my Jeep without thinking twice about it.

 

[Jerry Bransford]

And here I initially thought from you asking what that shim was and saying that it being loose was terrifying you that you were over your head here. I guess you can just never tell what someone's actual expertise level is from their questions.

 

[jeep_boss]

And here I initially thought from you asking what that shim was and saying that it being loose was terrifying you that you were over your head here. I guess you can just never tell what someone's actual expertise level is from their questions.

I had never seen a shim as thick as the one on the outside of the right bearing cap. That shim is larger in diameter than the bearing race of the bearing next to it to the left. There are two thin shims on the left side that are in place and there are no signs of damage to the bearing on the right.

I guess some people would rather pay an expert (if they can actually find one) than take the plunge to learn themselves - to each their own. I'm not one to put a box around myself for learning to be self-sufficient, this differential is science - but far from brain surgery.

 

[jeep_boss]

And here I initially thought from you asking what that shim was and saying that it being loose was terrifying you that you were over your head here. I guess you can just never tell what someone's actual expertise level is from their questions.

One other thing RE: identification of that shim —- try and find a visual reference somewhere of that thick shim somewhere on the internet..

 

[Jerry Bransford]

One other thing RE: identification of that shim —- try and find a visual reference somewhere of that thick shim somewhere on the internet..

That's the standard shim that comes in all TJ Rubicon Dana 44 axles, all come with that exact same shim for the Rubicon's carrier/locker. There's one on the other side too.

When the carrier bearings are in good condition, it takes quite a bit to seat the shim as you can see from the BFH I'm using below. This shows the driver's side shim which is similar to the your loose fitting passenger-side shim.

 

[Rob5589]

Many differentials use shims outside the carrier bearings, and far thicker. That particular locker requires outer shims as opposed to the standard set up which is behind the bearings.
The guy you spoke to was, less than honest, I will just leave it there. You don't need a spreader, we never used or even had one in the shop. At this point, the carrier will just fall out due to how loose the shims are. Like previously said, the carrier bearings are either bad or the preload was insufficient at set up. You can easily remove the carrier and check them out and post up some pics.

 

[jeep_boss]

Many differentials use shims outside the carrier bearings, and far thicker. That particular locker requires outer shims as opposed to the standard set up which is behind the bearings.
The guy you spoke to was, less than honest, I will just leave it there. You don't need a spreader, we never used or even had one in the shop. At this point, the carrier will just fall out due to how loose the shims are. Like previously said, the carrier bearings are either bad or the preload was insufficient at set up. You can easily remove the carrier and check them out and post up some pics.

I put my Jeep up on stands today and tested that same theory on advice from a friend of a friend who had a former life with ARB .. despite the one relatively loose thick outer spacer (he said it was more of a spacer than a shim), it was in there tight and wouldn't have come out without prying it out. The shim/spacer on the end might be loose by 0.001"... when it is cold (~35-40F) I can apply a few of pounds of force it move it slightly. When it is warmer like it was today (~60) it doesn't move.

I'm told this is not exactly great, but it is fairly common and it isn't at all likely to be catastrophic. The wear patterns on the ring and pinion also look normal to him, so I'm not going to view this as hair on fire.