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Unread 04-18-2010, 12:15 AM   #1
Avian
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Throw out bearing failure, knocking

My TOB is starting to make noise (at only 30k miles) and, of course, its not covered under my lifetime warranty because its a part in the clutch assembly.


I would rather NOT have the dealer fix this for $1,500, nor do I really want to spend $400 on an entire new clutch kit and fix it myself since the rest of the clutch assembly feels and operates as it did at 50 miles. After doing a brief search, I have found TOB's for my vehicle in the $50-$60 range. Since I have never done a clutch before, I was wondering a few things.

1: Does the TOB have to be "matched" to the clutch assembly, or can any TOB work for my model?

2: Can I just install it and go? Or do I need to "prepare" the clutch assembly in some way?

3: Can I leave the clutch and pressure plate attached to the flywheel, or must that be removed in order to remove the TOB? (I have no alignment tool)

4: How long does it take for a TOB to get "bad"? I just noticed this sound, and its still rather quiet. Am I looking at a failure (loud sounds, not catastrophic failure) in a few hundred or a few thousand miles?


I understand that since I already have everything apart I should just put a whole new clutch kit in, but this is (so far) just a leased vehicle. Id rather not add a new performance clutch if Im just going to give it back, and frankly, $50 is a WHOLE LOT better than $400 for me right now.




The issue:

A week ago, I heard a faint sound similar to rod knock while idling with my doors off. I thought not much of it since I figured it was engine related, and therefore a warranty issue. But today I heard it again from the inside of the vehicle with the top and doors on, still faint. With my head underneath the vehicle the sound was more clear, but by no means loud. The sound goes away as soon as any pressure is applied to the clutch pedal. My conclusion: TOB is beginning to fail.

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Unread 04-18-2010, 09:40 AM   #2
JeepnBeer
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I probably have about a half-dozen clutch replacements under my belt, so I am by no means an expert, but I will share what I have learned;

1. The TOB is specific to your jeep, but not necessarily specific to your clutch. You should be able to replace it with a TOB that is made for a stock JK clutch without a problem.

2 & 3. Yes, you can replace it and go. Once you remove the transmission, the flywheel will be mounted to the engine, and the clutch and pressure plate will be mounted to the flywheel. The TOB will inside the transmission bellhousing, and will be relatively easy to swap out once the transmission is removed. I would suggest checking out one of the TJ writeups with pictures. I know it won't be exactly the same, but it should give you a good idea on the scope of the job.

4. Its not unheard of for a TOB to start making some noise at 30k. Like most wear parts, it all depends on use/abuse, manufacturing tolerances, etc. If it were my Jeep, I would keep my ears on it and see how quickly it seems to be getting worse.

That being said, I have to say, like most people on here will probably suggest, you need to replace the entire clutch assemble. Yes, its quite a bit more money, but I think once you get in there and see how much work is involved getting to the clutch, you'll understand why people replace them when they are in there, irregardless of the miles. If you have to live with some bearing whine for a couple of weeks while you save up, I would consider it.

When you do the job, I would highly recommend you use the forums for any questions. The technical experts here have helped me through countless projects, and know Jeeps well. Good Luck!
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Unread 04-18-2010, 11:50 AM   #3
Avian
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I still agree with just changing everything out while Im in there. I have done quite a few trans jobs before, but nothing with a manual. But like I said, I have more time than money right now, and this is just a lease which is only going to be mine for another 12 months (If I decide not to buy it out).


Someone from another forum posted this in response to the same OP. Any thoughts on it?


Quote:
if your throw out bearing is knocking then you have other things going on.
normally a TOB will squeal or chirp as it goes bad. if its is making a knocking noise under load that means your pressure plate may have a broken spring of you have a failed lever if its a 3 finger. if you have a knocking from the engine under load then your crank shaft thrust bearing is going out and when you push the pedal the crank is moving forward. another posibility is a broken clutch fork or input shaft nose piece. if the nose piece broke then the TOB is no longer centered on the clutch fingers and is wearing them off center and it can knock that way.
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Unread 04-18-2010, 12:53 PM   #4
wranged
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I had a '07 that had two TOB's replaced under warranty. Do not know about '08's, but there was a TSB and a known problem. Had mine replaced at 20K and 35K.
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Unread 04-18-2010, 01:03 PM   #5
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Quote:
Originally Posted by wranged View Post
I had a '07 that had two TOB's replaced under warranty. Do not know about '08's, but there was a TSB and a known problem. Had mine replaced at 20K and 35K.
I tried to get the dealer to accept the TSB, but they said it didnt apply to my model. That, and the TSB describes a squealing noise, while mine is a knocking sound.
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Unread 04-18-2010, 04:11 PM   #6
dirtyjpwrangler
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definitely try a few dealers before attempting to pay for it yourself or fix it yourself. I had my TOB replaced under warranty at 32k. They'll most likely give you an entirely new clutch (which aint a bad thing)
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Unread 04-18-2010, 04:27 PM   #7
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The JK clutch has a diaphragm.. this finger deal is not applicable.. Once a clutch disc start wearing or warping the diaphragm moves towards the transmission and will put more pressure on the clutch release bearing (TOB) and this might create some undesirable noise in neutral with the clutch released..
I don't know if releasing/bleeding the line pressure of the clutch master and slave circuit will help.. I haven't studied the hydraulic clutch circuitry yet...
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Unread 04-18-2010, 05:56 PM   #8
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Quote:
Originally Posted by USAntigoon View Post
The JK clutch has a diaphragm.. this finger deal is not applicable.. Once a clutch disc start wearing or warping the diaphragm moves towards the transmission and will put more pressure on the clutch release bearing (TOB) and this might create some undesirable noise in neutral with the clutch released..
I don't know if releasing/bleeding the line pressure of the clutch master and slave circuit will help.. I haven't studied the hydraulic clutch circuitry yet...
Do you have a link to any technical drawings of this setup? Ive never seen the inside of a JK trans, and would also like to present it to the chrysler tech that gave me that info.
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Unread 04-18-2010, 06:02 PM   #9
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Well on a completly off topic note, my little 4 banger BMW is making this exact sound. Never thought anything of it til this
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Unread 04-18-2010, 07:19 PM   #10
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Quote:
Originally Posted by Avian View Post
Do you have a link to any technical drawings of this setup? Ive never seen the inside of a JK trans, and would also like to present it to the chrysler tech that gave me that info.
This is not a technical drawing but it for sure will give you an idea about the inner workings...



The slave clutch cylinder pushes against the RH end of the clutch release bearing arm/fork (13) and arm pivots over the support pin (11)..
(9) seems to be a shim....so shimming should be possible and this will alter the position of the arm/fork against the release bearing..

The arm/fork is held in place over the pivot by means of a spring (10)

Another possibility, besides a worn disk, is a sticky or dragging slave or master cylinder plunger..if the clutch is released and these plunger(s) is (are) sticky, a residual pressure onto the clutch release bearing might occur...
Just more background info..
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Unread 04-18-2010, 08:28 PM   #11
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wait for it to squeal and let the dealer take care of it....
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Unread 04-18-2010, 08:36 PM   #12
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Oh, I know how a whole generic clutch assembly operates, but I was rather curious to see how this diaphragm system works, and if there were any surprises to be found as a result.

By the looks of that drawing (assuming JK trans shown), it looks like once the trans is pulled back, I can just slide off the old bearing and slide on a new one, correct? There is no fastener system holding the bearing to the arm or clutch spring?



Quote:
Originally Posted by JerseyJeep View Post
wait for it to squeal and let the dealer take care of it....
The TOB, pilot bearing, clutch, pressure plate, and flywheel are not covered under the lifetime warranty under any circumstances over 12k miles. My dealer is not going to get $1k in labor to pull the trans back.
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Unread 04-18-2010, 08:58 PM   #13
USAntigoon
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Quote:
Originally Posted by Avian View Post
Oh, I know how a whole generic clutch assembly operates, but I was rather curious to see how this diaphragm system works, and if there were any surprises to be found as a result.

By the looks of that drawing (assuming JK trans shown), it looks like once the trans is pulled back, I can just slide off the old bearing and slide on a new one, correct? There is no fastener system holding the bearing to the arm or clutch spring?





The TOB, pilot bearing, clutch, pressure plate, and flywheel are not covered under the lifetime warranty under any circumstances over 12k miles. My dealer is not going to get $1k in labor to pull the trans back.
Here is the clutch and disk .. The diaphragm sits against the front of the release bearing..



Once you do a split, you might as well look at the disk condition by removing the clutch housing/pressure plate.. be sure you mark the pressure plate position towards the flywheel.. also remove the bolts evenly.. Also check the clutch disk for runout (put it over the input shaft spline and rotate the clutch disk.. you might use a dial indicator for that. the spec is .020 or less measured 1/4 inch away from the disk O/D. ) and check for excessive wear as well..

During re-install be sure you have a disk alignment tool otherwise you will experience hell in reassembly...

p.s I will never do that myself as I don't have the proper tools...
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Unread 04-18-2010, 09:14 PM   #14
Avian
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The last sentence is exactly why I just want to replace the bearing and not fool around with the clutch. I dont have an alignment tool. I know its dumb to have everything apart and not even look, but as it stands everything feels and operates a-ok in the clutch itself. That, and it only has 30k easy miles. I dont crawl rocks with it, so the clutch never gets "ridden", and it does not see deep water. Also, this is still a lease to which I am not sure about buying out. If I knew I was going to buy it out, I would slap on a new SPEC clutch kit. But no way am I going to dump $400-$500 on a part to replace a functional OE part just to give it back to the dealer in 12 months.

From what Ive seen though, most clutch kits come with a tool, so if I ever have to go through with a full replacement, it wont be a problem.
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Unread 04-18-2010, 09:19 PM   #15
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Quote:
Originally Posted by Avian View Post
The last sentence is exactly why I just want to replace the bearing and not fool around with the clutch. I dont have an alignment tool. I know its dumb to have everything apart and not even look, but as it stands everything feels and operates a-ok in the clutch itself. That, and it only has 30k easy miles. I dont crawl rocks with it, so the clutch never gets "ridden", and it does not see deep water. Also, this is still a lease to which I am not sure about buying out. If I knew I was going to buy it out, I would slap on a new SPEC clutch kit. But no way am I going to dump $400-$500 on a part to replace a functional OE part just to give it back to the dealer in 12 months.

From what Ive seen though, most clutch kits come with a tool, so if I ever have to go through with a full replacement, it wont be a problem.
Good luck and please let us know how it went...etc... very good thread...
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