Something lose in oil pan?
 

Well long story short,I took the xj to a shop last month to get the exhaust manifold replaced.(I dont have time or the space). The manifold was brand new. Either way just two days ago a noise started coming up from the engine. It's not a "knock-knock" type of sound. More like as if something like a washer or screw was lose in the oil pain. The truck runs perfectly. No engine light,no stalling,no lose of oil pressure,etc,. I took it to the muffler shop cause first I thought it had a "leak" on the exhaust since the noise it makes sounded like there was a hole on the muffler. They told me i was better off taking it back to the shop where I took it and have them drop the oil pan. Any one got any clues? I got a cell phone video I'll see if I can post up. Its a 97 xj straight 6, 158k. I did an oil change about two months ago. The engine sounds as if it was running a lil dry/low on oil buy at the same time like there is something loose inside the block. When it's on park it makes the noise but when I put it on any gear the sound completely goes away.

Have you checked the oil level?

Yes it's fine. I've read it could be the flexplate?

Yes, some have had knocking due to bolts walking out. I believe one member was driving through canada and thought he'd destroyed a motor.

Does the trans have to be taken out to check the bolts?

I..THINK...you can check via an inspection cover, but I could be wrong. Crawl under, see if there is any cover near the bell housing-ish....

Yeah I checked last night. It has like an aluminum cover right next to the starter.

Yeah go ahead and take off the (4?) bolts for the inspection plate and check the bolts on the plate. I had mine loose, and it had a nice clunking rattle at idle, but couldn't hear it very well at speed due to all the other noises.

You will probably have to look this up because I do not know the terms, but there is a nut someone else has to hold onto to keep the plate from spinning when you tighten the bolts up, and they will also turn the plate so you can access every bolt. Make sure to unhook the battery so you do not turn your jeep over and start it when you spin it. Not likely to happen, but might as well be safe.