hey guys.. my 96 4.0 zj is making this metallic clatter/rattle/ tinkatinkatinka noise at idle speeds in any gear range under engine. when engine is cold then started ther is no noise at all then like 10-20 seconds after the noise starts coming on. i first heard this noise start the day i put on a new muffler & as soon as i started it up the noise was there. so i even returned that muffler for another one & a new cat ,header,o2 sensors,motor mounts,tranny mounts,harmonic balancer, checked flexplate bolts.(tight). & checked for loose tranny bolts, pulled one plug wire at a time.(no change) one injector wire at a time.(no change) . checked distributer shaft is tight, & thrust bearing seems fine.(no in & out play). pulled oil pan & all looked good . oil pressure is great. 38-40psi. no mechanic of tranny place has a answer. even pulled valve cover & all seems good. it has that diesely type sound at oil pan/bellhousing. i have a new flexplate. im about to drop my tranny as a last ditch effort. the engine runs great. just this clear clattery noise. ive searched evey forum & thread & most threads just die off before it gets any where. other than this noise the jeep runs strong. thanks in advance for any & all help. lets her what ya got guys.........

 

I'm unclear, is it idle in gear only or is it when you are moving but not accelerating?

In your best guess, what area does it sound like it is coming from?

 

its at idle in p r n d 1 2)sitting still at a light. it sounds like its right at the bellhousing/oil pan with a stethascope. but if you put your head under front of jeep it sounds like there. kinda like a diesel. once you drive for a while the clatter noise kinda turns into a clicking. ( like baseball card in a bicicle wheel going slow.

 

Did you do a visual inspection on flexplate to make 100% sure it hasn't got q crack in it?

 

yea ive spent hours under there.lol.. ive taken every bolt out . & see no cracks. i was thinking maybe the bolts maybe got streched out. i dont no. the second i put a new exhaust on & started it up. bam.. the noise was there. i had the whole system welded. soo. im going to take off the cat back & see if the noise still happens. i just bought a flexplate & tranny jack. so i guess that will be my next move. this noise is unacceptable.. it drives me nuts. thank you for your input bro..

 

Did you remove the exhaust system from the engine and try it after that?
I know it would be loud but something is causing the click etc!

 

Could also be inside the exhaust. Broken convertor guts.rattling inside the housing. Also check the heat shield.

 

i havent unbolted the exhaust at the header yet. but the header is new the cat is a year old & heat shield is clamped & i replaced the muffler twice (dynomax turbo). maybe because i had a crack in my header for the year i had put new cat on that it killed or partially clogged the cat? i used my vacuum gauge hooked to intake and its at 17-18 hg at idle but when first started it hovers at 15 hg. which says advanced timing at 15hg. but my OBDII scanner says all Moneters are good. adv. timing 17 at idle & map is 13.3. my O2 sensors are ngk & 1 year old.

 

I had the same problem in my first jeep. it was the torque converter. check it out.

 

i was thinking that. whats the best way to check the torque converter. i did a stall speed test & got 1900 rpm's. the converter also has not been locking up at highway speeds lately. i dont no how else to check it.

 

Just check all the bolts and make sure they are tight. That's what I did

 

the dynomax muffler was installed backwards. man yoe would swear it was a cracked flexplate/wristpin 7 differant shops couldnt figure it out. while doing a oil change tonight i took my hacksaw to the muffler & when i started it up. i could'nt believe it. no clatter. a year & a half replacing everything but the frame.lol. i so happy this is over. thanks for all your help guys. oh the offset pipe side of muffler is the inlet & the centered pipe is outlet i guess. it dont look like it will fit like that but ill see tomorow.

 

wow. Last place I would have looked tbh.

 

NOT FIXED. i put a brand new stainless header,cat & muffler (magnaflow) & its there. at cold start rher is no clink noise until 30 seconds into warm up then tink tin tin. & after a 20 minute drive is seems to be 95% done. until i shut down & re-start a little later. & the whole thing repeats. no noises up top.(pulled valve cover) did notice #5 cylinder pushrods are bearly spinning at ide. while all others are really spinning. i pulled all pushrods & were straight. no up & down play in lifters. but some side to side play in rockers by grabbing wth hand . ive heard thats ok. b-cause there is nothing supporting the rocker to stop that. it clinks to the vibes of the engine like. loudest at the rear main seal area. oil pan. i cant find it on a 2'' spot of flexplate on corner of teeth there shinny. but it dont appear to be wobbleing ive checked starter for contact & nope. even shimmed it. & pulling plug wires one at a time dont change nothing. what the hell is it.

 

make a video with sound of course and post it up, would be easier to help you with.......