I believe I just fixed my Jeep JK throw out bearing issue. First, I am not an auto mechanic but I do run the Maintenance division for the USS Carl Vinson aircraft carrier's 10,500lb hydraulic weapons elevators and am very versed in mechanics, repairs and hydraulic systems. I have a 2011 Jeep JKU sport with 60k miles. In those 60k miles I have put 3 new clutches and 5 new TOB's in. Sounds excessive right? Pointless is more accurate. I packed my stock clutch with mud at 7k miles and blew the friction plate. I had a very reputable 4 wheel shop install a centerforce dual friction and right off the bat I had a ticking sound anytime I wasn't pressing the clutch. If I pressed the clutch in at least an 1-2inches, the sound would go away. I called centerforce and they told me it was normal due to the centrifugal weights. 11k miles later my throw out bearing failed and burned up the fingers on my pressure plate. I had another TOB and dual friction clutch in by the dealer. The ticking from the TOB was still there but even louder. 20,000 miles later my TOB went out again but luckily it failed instantly and didn't machine my pressure plate fingers. I had the dealer install a new TOB and requested a master Tech inspect everything to find any underlying causes. He didn't find anything and gave me the standard After market clutch speech. I drove the Jeep another 15k miles with that annoying ticking sound until AGAIN the TOB went out... By this time my wife is ready to drive it off a cliff ( luckily she can't drive a standard ). By this time I felt about the same so even though there was nothing wrong with the latest centerforce, I swapped to a Spec 2+ while the local shop had the bell housing opened up. Guess what... ticking sound was exactly the same. 50 miles ago the chatter got significantly worse and I said enough was enough. I broke out everything I could find on the jeep clutch system, read countless posts on the various forums and reserved a lift at the auto shop on base. if anyone was going to screw up my clutch this time it was going to be me and I wanted to do some trouble shooting. MAN DID I FIND ISSUES! First, I left the slave cylinder pressurized and removed it from the bell housing. At this point you can measure the distance from the clutch release fork to the mounting plate of the slave cylinder to determine the length of the plastic slave cylinder piston when installed at rest. If you then mark the length you measured on the piston rod I found that at it's resting point, there was hardly any preload pressure on the release fork. I mean VERY minimal pressure in the slave at that extension distance! Now keep in mind that it is an enclosed hydraulic system from the master cylinder to the slave that maintains even pressure. Clutch pedal depression builds pressure and the spring pressure of the pressure plate returns it. The further the slave piston is pressed into the cylinder the greater the pressure is. By having too far of a distance between pressure plate contact and the bell housing slave mount plate the less pressure is built up in the cylinder and maintained on the throw out bearing. Not enough and the TOB will be making contact but it will be jumping around against the pressure plate causing the chatter. I tore apart the bell housing and kept digging deeper. Before the job I got a new release fork, pivot stud and 3 washers based on the TSB for the "unusual vibration for jeeps with less than 12k miles" When I had all the components off, I compared them with the new equipment and found the following: My release fork powder coat was slightly worn/grooved where it contacts the TOB causing it to not slide horizontally as smooth as it should (not a huge deal but I replaced anyway) my pivot stud at first glance was fine. when compared to the new pivot stud, it was compressed 1/8 inch shorter than the new stud. the Teflon ball that the release for rides on was also slightly oval instead of round, I replaced that as well, for the stud and fork at the dealership, it came to 70 bucks (not bad). Even with the new parts I was still 1/16 of an inch off of what I wanted based on the pressure test I did in the beginning with the slave cylinder piston. I removed the 1/16 inch small washer that was between the pivot stud and the bell housing and put 2 new washers coming out to 1/8th inch spacing. The new throw out bearing was exactly the same length as the old one so I didn't need any correction for that. In all, my issue was: Worn pivot stud in conjunction with the spacing I corrected with the washers was about 1/4 inch off from stable pressure on the TOB. I definitely recommend either getting a new stud to compare or measuring the distance to see if you are missing more space than will be corrected with the service bulletin washer fix. Now it is running like a dream!!!! Not a single sound coming from the clutch and very smooth foot pedal feel! Because I had such a hard time finding answers on these forums or correlating my issue with others, here's some details on what I was experiencing. By chatter on the TOB, I mean a clicking or ticking sound that stays consistent with the RPM of the engine. This was not a squeal you might hear if the TOB was seizing up. At idle it is slow, push the gas and it gets faster. The sound completely went away when the clutch was depressed slightly ( just enough to build pressure but not enough to actually disengage the clutch at all, 2inches roughly.) This is not a rattle sound that fluctuates pitch on it's own. It sounds very similar to a sewing machine.

 

Nice write-up, and good troubleshooting. The professionals are faster, but faster is often only better at flat rate. When I replaced the clutch in mine, a new release bearing had a backwards wound retainer spring that might have kept it from pressing squarely up to the release fingers with just slave cylinder's internal spring pressure at pedal-up -- pic is here.

 

 

That was exactly the issue I had on my Jeep. I took it to Will at Centerforce a year ago and they fixed it for free. They asked me to bring in my Jeep since at the time they did not know what was causing the noise.

 

My 2010 started doing this last fall.

 

I just put in a centerforce clutch kit in and the TOB still rattles. Once it warms up it’s not so bad or if the ac is off. Once the clutch is fully depressed the sound goes away. I didn’t how ever not change the fork even though it had some wear on the pivot points due to being out of money and needing my Jeep back on the road asap. It drives just fine but that rattle at idle sometimes is just no bueno. Oh also if I depress the clutch a few time the rattle goes away then it can idle with hardly any rattle. What’s your take on it OP?

 

If the noise goes away with about 1/2" press (or less) of the clutch pedal, then the problem is likely what the OP described (lack of slave cylinder force on the clutch fork when the pedal is up).

 

couldn’t hurt to replace. Although I’m not sure how to set the slave cylinder, because if I read correctly that’s what he had to do.

 

Nope, not the slave. He replaced other parts to get pressure on the fork...

 

oh sweet. Then it should be a simple plug n play. I know his jk is different from mine but virtually the same concept.