Knocking sound coming from in between engine and tranny???

[8700XJS]

I am curious about the knock I may or may not be hearing. What I think I am hearing is not very loud and I have to actually lean down to hear it. I certainly cannot hear it while sitting in the Jeep. Does this sound like the symptoms of the loose flywhell to torque convertor bolt.

Kenny

 

[firegod33]

A friend had a similar problem, recently. The problem turned out to be the dustshield hitting the flexplate. A little bend, here and there, no more noise.

 

[JEONLYEP]

When the bolts loosened on my XJ's flywheel, it was really noticeable in cab. but only at certain RPM's.

Daryl

 

[tnomud]

Mine sounds more like a deisel at idle. It almost sounds like it is coming away from the cat converter???

If it is the flexplate bolts, i just drove 800 miles on it. The sound is typically there at idle when it is cold, and seems to go away when it warms up or the revs go above 1200 or so. It still does it in neutral and park too.


Do the cat converters ever break apart inside?

 

[8700XJS]

In my previous post I thought that I might have the loose flywheel bolts but after doing some research and talking to other XJ owners I don't think it is loose bolts I was hearing, but a 4.0L I6 thing.

Don't know if this is the same. Should be since the motors are pretty much the same. This next bit I found sounds like it addresses the piston slap issue to me.

"I have a 1997 Wrangler, with a 4.0/a. Why is my engine so noise? It sounds like a diesel. It get 89 octane gas, 10w/30 synthetic, everything is current on fluid changes and levels, nothing appears to be damaged. My friend's TJ does the same thing."

I had the opportunity to discuss this with a Chrysler engineer. Chrysler was trying to eliminate as much weight as possible from the engine block and removed a lot of material from it. This made the engine very noisy. Complaints about this led to Chrysler reversing their decision and adding more iron to the block for the release of the WJ, which runs dead quiet. There is nothing wrong with your engine, just look at the noise as a weight and money savings for your Jeep."

Also I did find a class action lawsuite against DC for the Diesel sound.

It states this "..., plaintiffs alleged that Chrysler's model years 1991-95 Jeep vehicles with 4.0 liter (4.0L) and 2.5 liter (2.5L) engines were defective due to an idle knocking noise in the engine..."

Very interesting reading with engineers inputs and everything. Some 20 pages of reading.

 

[89xj]

Do the cat converters ever break apart inside?

yes, very common, but it usually makes a rattling noise.