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Rear Dana 44 Rattle / Noise caused by shims coming out of place?

MigGunslinger

Red Skull Member
Joined
May 21, 2020
Member Number
909
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572
Loc
Sacramento
I have been trying to track down an annoying noise on my 06 TJ Rubicon that has been getting consistently worse, it happens when I am coasting or lightly accelerating under 20mph. Essentially a very loud rattle. It was quieter when it first started and I could not track down the source but now I am almost positive that it was coming from the rear axle.

Suspecting a pinion bearing I drained the fluid and pulled the rear axles this morning I then used a drill with a socket to spin the pinion producing a vibration or rattle. But when I went to pull the carrier I noticed what look like thick shims on each side of the carrier bearings had escaped the bearing caps and the only thing that kept them in place was the axles. These two thick shims are the only shims present at the carrier bearings one at .130 and the other at .142.

Drivers Side:
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Passenger side:
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I had 4.88s put in at a reputable local shop a couple of years ago. Is it normal that a gear shop would set up an axle with just 2 thick shims like this?

After removing the carrier and spinning the pinion with a drill again the vibration seemed to be gone.

There are also a couple of odd marks on the ring gear and what seems like a weird wear pattern. I will dump a bunch of pictures if anything jumps out at you guys please let me know. I am wondering if I should just dump new bearings all around and see if it fixes the issue unless my ring and pinion are junk.

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Is it normal that a gear shop would set up an axle with just 2 thick shims like this?
Most likely they shimmed the carrier by shims under bearings. Moreorless the 2 thick shims used as ‘coarse’ shim and ‘fine’ shim under bearings and the thick 2 shims are much more manageable and not easily get destroyed when installing or removing from housing.
 
Any pictures of carrier bearings?
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I can't feel the lines on the bearing race but they don't look great.
Most likely they shimmed the carrier by shims under bearings. Moreorless the 2 thick shims used as ‘coarse’ shim and ‘fine’ shim under bearings and the thick 2 shims are much more manageable and not easily get destroyed when installing or removing from housing.
Totally understood. I thought the same as well but if there are shims between the bearings and the carrier they are too thin for me to see.
 
They’re fucked. Without a doubt. And that’s why your carrier came out easily due to loss of carrier bearing preload and the noise you was hearing.

New bearings and you should be good to go. Your ring and pinion looks fine to me. I’ve seen worse.
 
Thick are oe style and were commonly bought as a big fucking stack in increments.
Lots of axles use them but build stackers are much easier to tune thickness and way less expensive.
 
Well, I have a rebuild kit coming with new bearings and shims. I’ll just re set up the carrier with proper backlash and preload and check the pattern.

The axle does have a few wheeling trips on it including driving it to Colorado, Moab, Rubicon, and Barrett lake. I also DD it. Not sure what happened to it because I wheel like I have to drive it home lol.

I paid 2200 to put gears in this thing, maybe I just got fucked over like I always do. I have a case spreader and some other tools coming too. I’ll just do it myself from now on.
 
I question whether or not it was set up with too much bearing preload and caused the excess wear like that....
 
I question whether or not it was set up with too much bearing preload and caused the excess wear like that....
it was proven that you cannot have too much carrier bearing preload. Actually, I've read they encourage to put as much preload on carrier bearings as possible, as it will help with ring gear's deflection under heavy load.
 
I question whether or not it was set up with too much bearing preload and caused the excess wear like that....
Like I said the 4.88s were set up by a local shop with a good reputation and I changed the fluid at the recommended break in time.

It would not be the first time that a shop with a good reputation has let me down.

Edit: is the consensus that with the proper preload the shims would not have come out even though they are not covered by the bearing caps? So the shims coming out is a symptom of the problem not the cause?
 
Small update: My bearing puller came in today. Good call on that.:lmao:

The pinion bearing and drivers side carrier bearing came off with little drama but there was no way to get the clamshell over the Passenger side bearing because of the air actuator. For those who do not know, the TJ Rubicon's came with air lockers that actuate using 5-8 psi. The rears have a limited slip as well I think and are known to be a bit weak but they have worked for me so far. I absolutely did not want to wreck this stuff as there are little to no parts out there to fix them. I am sure there is a special Mopar puller attachment for this that costs $1000 or something:

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First I tried modifying my 2 jaw puller to get under the bearing where there are notches in the carrier. This was a bad idea, not strong enough and it came apart on me at mach speed.

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Next I tried using half of the clamshell and strong language. This got the bearing started and up far enough that I could put both sides of the smallest clamshell under the bearing and finish her off.

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Another small update:

I got all of the parts and tools in. bearings are pressed on and races installed. used a pick to get about 1/2" of silicone out of each of the cover holes and cleaned up the gasket surfaces.

I decided to use the original pinion depth and preload shims as a starting point and the preload looked good with 30 in/lbs being right in the middle of spec. Hopefully the pinion depth is good too but I will have to see the pattern for that.


Things were going good, I did end up with a case spreader and I am being cautious with it but it makes getting the carrier in and out much easier. Backlash started at .018 and I moved the smallest shim from one side to the other and it now sits at .010, spec is .005 to .008 so a bit more fiddling needs to happen.

I had to stop last night because the ears on the actuator (last pic on my previous post) decided that they did not like the specified 80 ft/lbs on the carrier bearing bolts and that they would rather squish out and split :eek:

Fuck, these things are unobtanium. I managed to keep one of the ears intact and it is doing ok with a washer over it. The other split and I can not get it torqued to spec. Current plan is to tack weld it back together with a wet rag over the actuator to keep heat and sparks off of it. No pics because I rage quit without cleaning up last night.:homer:
 
Well I got the ear tack welded back together and it held up through several more times being torqued down:

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I also got pissed off because it looked like Yukon did not include any pinion depth shims but it turns out they sent some that fit under the pinion bearing race. :homer:

I got a pattern, It's not perfect but I'm going to run it. I made a couple of changes to the pinion depth with only slight improvements. Per Yukon's instructions on setting up used gears I was looking more at the coast side.

Test drive went good so I will take it on a few longer drives before calling it 100% fixed.
 
After a few months I have figured out what the initial rattling noise was that caused me to tear the rear end apart.

When I installed the 3" currie springs and bump stops the rubber isolator would not work with the upper bump pad so I left it off. The extremely loud rattle was the top coil of my spring vibrating against the spring perch.:homer: I cut out the centers of the old isolators and wrapped the top coil of the spring with electrical tape where it goes around the aluminum retainer and the noise is gone.

The newfound silence from my springs led me to many more new and exciting noises coming from the rear end.

First, my 35" MT Baja MTZ tires were severely out of balance and out of round with about 1/2 tread life left.

Second, The semi-float axle bearings had some play in them which I had to bend the retainers back straight to remove. (could out of balance tires bend these retainers out over time?)

Third, my parking brake was dragging slightly, if I adjust for no drag the brake does not work If I adjust for the brake to work the pads drag. so frustrating. (Rear disc with internal parking brake drum)

I am constantly messing with the rear parking brake and have taken to just adjusting them in fully to shut them up, the parking pawl is going to have to hold me:mad3:

Last but not least the vibration stopped at idle is crazy, In drive with my foot on the brake. I have checked the torque converter bolts, the motor mounts are 1" brown dog rubber mounts. The transmission mount is the standard GM rubber piece on a custom crossmember (I am going to try and modify this to use the stock Jeep mount soon) Here is the really weird thing: I was wheeling this weekend and noticed that in 4-low under the same conditions it has almost zero vibration. It is also noticeably better in the morning when it is cold outside than in the afternoon when it is 60+ outside.

Anyways this was a slightly off topic ramble in an older thread but if anything jumps out at anyone feel free to post it up.
 
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