Hi there friends. I have been using this forum for a while and it has been incredibly helpful. I am running a 98 Xj lifted. Today I have a noise coming from what seems to be the bell housing area. The noise is not really a knock or a tick it's more of a Thack. Since I have owned the jeep it has made a ticking sound on cold start up and then went away. Over the last few days the sound has gotten louder and now is persistent. It speeds up with acceleration and becomes more high pitched and is present in park and neutral. Oil pressure seems to be holding steady. I have pulled the plugs one by one while engine running and no change in sound or pitch. I peeled off the bell housing inspection plate and re torqued the flex plate bolts. 2 of 4 were easy to undo. Still sound is still present. I have put a srewdriver to all the head bolts and areas to try and pin point it but all I hear is mechanical swirling nothing like the noise. Any help would be greatly appreciated. Next I will take the belt off and run it to rule out the possibly of accessories.

 

I had a water pump go bad on me and it started making a racket.

 

A recording of the sound is worth 1,000 words.

 

Flexplate to torque converter bolts loose?

Use a stethoscope.

 

"It speeds up with acceleration".

First, try to identify whether it speeds up with engine RPM, or it speeds up with wheel speed. If you already know, post the answer. That will help narrow it down.

 

hi guys. Here is a couple short vids of the sound from inside the cab driving and from underneath in park. My phone was running out of memory so they are super short.
https://youtu.be/pIwnO3elYH8
https://youtu.be/o6rJoBy4hIQ

I have been driving it since yesterday and am leaning towards a exhaust leak around the manifold area. I have no noticeable loss of power, good oil pressure and the flex plate bolts are tight and with a stethoscope can't hear anything out of place happening in he block or head. Changes gears fine no funny sounds.

The noise picks up with rpms
not speed

The sound I found also dissipates to almost nothing when I find a sweet spot on the throttle at low rpms and then comes back as the rpms go up.

I think I would describe the noise as high pitch putt while driving.

When I get some time today I will inspect the mainifold gasket for cracks as well as the header (pacesetter) and exhaust pipes.

 

Could be a cracked flexplate where it bolts to the crank.

 

the flexplate looked in great shape when i inspected it, i pulled the bolts out one by one and looked for cracks around the bolt holes and re torqued. i also inspected the area around the center for cracks all looked good.