Adding shims or reshimming stock gears? New axle issues.

REDLYNER

REDLYNER

Mall Crawling Race Rig
Joined
Oct 31, 2008
Location
Mountain Island
I just swapped in a new to me (used) rear Rubi 44 into my TJ. The install went pretty well, but on my test drive I experienced some clunking from the rear. Took it to Meineke today have the brakes checked out and asked them to look for the "clunk".

Their diagnosis was that there was too much play between the ring and pinion and that is what was causing the clunk. Their suggestion was to add shims or reshim it.

Does that sound right? The clunk happens in forward and reverse and only on a start up. It does not happen while cruising. Just under the load of acceleration (forward or backward) and it only clunks once.

Anyone know the cost involved in that- reshimming or adding shims?



*I plan on having someone look at it- just trying to prepare myself for the costs involved and I wasn't sure what to expect.

Thanks-
 
What did you set the backlash at?
 
Do you have a locker?
 
Does it happen when you put it in gear (F or R) or do you have to actually press the gas for it to clunk.

If you have to press the gas for the clunk I'd check suspension bushings first...make sure they're tight and all...
 
You have to re shim....I don't see how you could just add shims to something that is suppose to have bearing preload to begin with (unless the bearings are chewed up). It is possible that it is suspension noise so make sure you check the bushings as stated above. Its not expensive at all to reshim that for the proper backlash if that's the problem and nothing else.
 
It is a stock Rubicon Axle- No prior gear work.

I installed it this past weekend. It's possible that a bushing could be bad, but it never made the noise on my old axle. First time it ever made the noise was the first test drive after the install of the new axle.

It does not make the noise when I put it in Drive or Reverse, only when it is in D or R and I start to accelerate. As an example, just sitting in my driveway, I can put it in drive and mash the gas just going 4 feet and it will clunk. Then put it in reverse and as soon as give it some gas, it will clunk again.

However, if I just let it creep, it does not clunk.

So next step- check the bushings for cracks and crumbles?

What I don't get about the shims- I haven't heard of a stock axle needing that. Is that common?
 
You can't just yank a pinion or ring gear and throw shims until it reaches the right backlash...you wont be any better off...little more to it then that...
 
Is it a limited slip? Only reason I ask is with alot of friction assisted limited slips without the right friction modifier the disc or cones grab and lock against each other, causing an audible clunk. Sometimes they even jerk a slight bit like a locker unloading. I've even experienced it driving in a straight line in a fresh auburn rebuild. If its an open carrier I'd rule out backlash. If it's that bad out and you get an audible clunk some bearings have gone very far south. Teeth would be climbing each other and breaking all sorts of stuff. Does it whine or make any other noise at speed? Still it sounds more like a suspension bushing binding or bottoming out if it accurs after loading the drive train once in either direction.
 
It doesn't whine at speed.

The axle does have a limited slip when not locked. I used the recommended gear oil- but didn't add any special additives.

I would think the limited slip would be a factor on turns, not on starts or reverse.

I'll check the bushings in the morning, although I didn't have these problems pre-Saturday install.

Thanks for the suggestions!
 
A limited slip like any traction device is more noticable in a turn. I did get the feel and noise from a very fresh rebuild on an Auburn unit, its a cone type. Under firm acceleration it would do this, the tires wouldn't break lose or chirp but for some reason the cones would unload or unlock and cause the feel and slight clunk. It was also found while driving around a parking area going forward, backwards and slight turns. No hard or sharp turns and not at anything over 15mph. We were breaking in a rebuild and had messed with the spring rates. I was taught to do this with limited slips to help work in and lubricate the clutch packs. You could also get a real good feel for what was going on, espeacially with street tires and quiet exhaust on mom mobiles. Ford had some issues with their SUV limited slips for awhile. Turns out customers wanted more road manners instead of a traction device you could actually feel work from time to time.
 
I drove it around today to try and get a better feel for when the "clunk" is happening.

If I accelerate slowly, it does not make a sound- reverse or forward. But if I give it some gas, clunk!

I'm starting to think it is suspension related because it basically clunks with the momentum of the jeep. Shift the weight forward, it clunks, shift it backwards, it clunks. Cruise or accelerate slowly= no noise at all.

Just looking at the control arms, everything appears to be in order. Also, I swear a couple of times it sounded like the noise came from my transfer case area.
 
I had something like this happen after I installed my 8.8, I did something very stupid to find out wear the noise was coming from. I layed under the jeep and had my wife hold the break and hit the gas so i could see where the noise was coming from. Very stupid not recomended but I did find my noise.

Turned out when I was installing the axle I had issues with where the Muffler shop put my tail pipe so I cut it the tail pipe off. But What I didn't realize is I left the exaust blowing directly on my top shock mount which eventually melted the bushings out of my brand new shock. So now i have to figure out if I can get a new bushing or do I have to replace the shock.
 
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