pro123

Well my first motor had 185000 miles on it and it started making a noise after it warmed up. It sounded like a hammer hitting a piece of wood. I thought rod or lifter, replaced motor with one that had 80000 miles and it still makes the same noise. What could this be has recent tune up, oil with additive, and great oil pressure. Could it be the trans or a lifter gone bad in this motor as well? I thought the catalytic converter coulda caused it but it seems to be working properly. Thanks for your help in advance.

Cherryokee

Is the front exhaust pipe (before cat) banging against the cross-member? Mine sounded like your description before I discovered the broken hangar/rod...

pro123

No that's still together I thought it might have been a hanger but their all intact. Thanks

pro123

Could it also have something to do with the transfer case? I just can't stop thinking that it has to be something that's original to the jeep. If one motor prior did it and now the new one does it has to be something that's original.

MonacaYankee

If you still have your old motor, start it up for a minute and if it does not make any noise you should put her back in before she gets mad.

grandersyo

does it only make the noise when its driving or in gear because the best way to find out is to just get your ear as close to the noise as possible. but if it makes the noise when you hit a bump or driving then you have a longer list of things that it could be. but give me a little more info like if its only driving and how many times it makes the sound like 1 hammer hit a second or multiple hits. im guessing its not from the engine.

Gmaster

If it makes the noise in park, it cant be the t-case couse nothin in it is turning.

pro123

No I don't have the old motor. The noise happens when its in park, reverse, neutral, drive, 3,2-1. It really makes the noise after it warms up. It's a constant hollow knock. It does it driving and sitting, when I put it in gear the noise seems to become deeper. While using my own ear and a scope the sound seems to be coming from the rear of the motor especially by the trans. I checked all torque converter bolts and made sure the fly wheel was ok and made sure the dust cover wasn't hitting. Thanks for the replies hope this clears somethings up

jjj_2083

Where does the noise sound like it is coming from? I had the same problem with my 88 and it sounded like it was from the oil pan. The problem turned out to be a hairline crack on the fly wheel that was almost invisible to the naked eye . If it sounds like its in the oil pan pull your inspection plate off on you fly wheel while its running and spray some WD-40 on it (pretty vigurously) if the noise goes away then its your problem, atleast that what I had done.

pro123

Like you said it sounds like its coming from the fly wheel area that's why I thought it might be the trans. But I'll have to try that wd40 trick. Because with my swap I used the same fly wheel and converter that was on prior.

jjj_2083

The other thing that I though it might have been is a Piston knocking but you said it does it when its warm right? and dont quote me on this but the piston knock should go away once it gets warmed up...Just had that thought

pro123

Ya it did it all the time, but went out tried wd40 trick didn't make any difference. I got curious and took one of the torque converter bolts out because something looked broke. Looked with a light and was just paint, so I tightened the bolt back up and drove it the next day and the sob doesn't make a peep like it use to, its very faint now. So this weekend I'm gonna take the other three out and put teflon on them and torque them down as much as possible. Hope this clears up the little bit of chatter.

pro123

Anyone know what the torque converter to fly wheel bolts torque specs are?

jjj_2083

Thats good to hear it would be a tragedy to lose another heep!

DaddyCat

Do not put teflon on your bolts, teflon is for sealing pipe threads.

Install the torque converter to drive plate bolts clean and dry to 40 foot lbs torque.