Knocking after clutch replacement

justinbird27

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Sep 2, 2022
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Salt Lake City, UT
I’ve been chasing this problem for a month or so now on my dad’s 2010 Wrangler Sport. He’s mechanically inept so here I am!
. I’ll start from the beginning.
His clutch went out. I’m trying to remember the specifics but I believe the clutch pedal was hitting the floor with no pressure at all. I started with the slave cylinder and After popping the first two 😂😂 I finally got the hang of it and it felt good but still wouldn’t go into gear. Decided to pull the transmission with the intention of replacing all the clutch parts and with special attention to anything noticeably damaged. The throw out bearing was clearly shot so I replaced it. I also replaced the clutch disc, pressure plate, and pilot bearing. Put it all back together and voila! Clutch felt great, shifted so smooth… however there was a slight rattle coming from under there somewhere. It wasn’t bad and I assumed the muffler was tapping somewhere. I didn’t have the time to look into it and figured it wasn’t a huge issue. I handed the keys back over to my dad and was on my way.
He came back maybe 2 months later and claimed the rattle progressively got worse and is now a violent knock. Pulled it apart, inspected things which all looked good, did a legit vacuum bleed of the slave cylinder. Put it all back and still the knock. The knock is constant with the speed of the motor, and doesn’t get better or worse whether the clutch pedal is pressed or not. I pulled it all apart AGAIN and replaced EVERYTHING. Clutch release fork, pivot ball, another pressure plate and clutch disc, another pilot bearing, another TOB, the spring clip that holds the clutch release fork to the pivot ball. I put grease where needed, ensured the slave cylinder is sitting properly. Pressure plate is torqued to spec. Used an alignment tool with the clutch disc. Only took me 5 hours starts to finish this time! But the knock is still there. No better, no worse. I’ve used a 3/8 extension as a stethoscope and it seems to very clearly be coming from where the bell housing meets the motor. I didn’t replace the flywheel since it looks okay, a couple burn marks but no grooving or anything. Should I have replace that from the start? I’m lost. He did mention that at some point in time he had no oil in his motor. He wasn’t sure why, there’s no leaks and he filled it and it’s been fine since but no telling how long he was running dry. I about pulled my hair out since that’s such important information, but I’m lost as to how or if that could be related and just baffled by the poor timing of it all if it really isn’t related to the clutch. Any guidance would be greatly appreciated!!!!!
 
Does the knocking sound happen in neutral while not driving, clutch pedal pushed in while in gear or while driving in any gear? Or is the knocking 100% RPM dependent? Also, Did you scuff up the flywheel with like 400 grit sandpaper or a scotch pad then use brake cleaner to clean everything off?
 
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Drove my 2010 2 door sport off the lot new. 15k later clutch and flywheel bitched. Had the Stealership put in another OEM. 14k later both bitched again. I have been driving stick for 47yrs, never had any problems with my other rides. Had my neighbor who has his own shop up the road ( and was a senior tech for Chrysler, Jeep) put in a ACT heavy duty clutch and flywheel. 25k later and I drive (F1) hard, no problems. He told me there is a history of the OEMs being crap. Good Luck.
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Does the knocking sound happen in neutral while not driving, clutch pedal pushed in while in gear or while driving in any gear? Or is the knocking 100% RPM dependent? Also, Did you scuff up the flywheel with like 400 grit sandpaper or a scotch pad then use brake cleaner to clean everything off?
I did scuff it and clean it with brake cleaner, yes.
And correct, the sound is always there… in neutral, reverse, or any forward gear, regardless of whether or not the clutch pedal in pressed. And the knocking gets worse/louder as the gas pedal is pressed and the motor turns faster.
 
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I did scuff it and clean it with brake cleaner, yes.
And correct, the sound is always there… in neutral, reverse, or any forward gear, regardless of whether or not the clutch pedal in pressed. And the knocking gets worse/louder as the gas pedal is pressed and the motor turns faster.
knocking noise that increases with rpm is never good. :(:(
 
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My 3.8 has been drinking copious amounts of oil from the get go in 2010. I can see the engine running out of lubricant over time with no signs of leaking. And no checking the level. Does not sound good.
 
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