Thank you very much for all the responses. Well, for what I can conclude after reading all of you guys comments is that my torque converter or my flex plate was replaced before and the bolts were not tighten enough. Going back to what Myanovich was saying, the flex plate is hard to crack. But yes, maybe at Chrysler, they didnt use any adhesive like the Loctite Threadlocker Blue on the bolts. But then if this is the case, then almost all Jeep Libertys CRD with automatic transmission would have had a cracked flex plate at 65,000 + miles... I still can't understand why this happened. The flex plate is made out of stainless steel and I suppose that the engineers at Chrysler designed the part to support x amounts of tensions and it wouldn't crack.
This is a video on how this whole thing is:
http://www.ehow.com/video_2327503_insta ... plate.html for a GM.
My KJ was bought in Argentina, not in Europe, so I don't know what do they send over here but it is called Cherokee instead of Liberty.
What I still can't understand is why the noise was very low before going to the mechanic and now, after they disassembled the surroundings of the flex plate to see it, the noise is a lot more... Then I ran away from the mechanic shop and I had to stop the engine because the noise was so loud. I wonder if I broke some other part or even the converter torque...
I would bet your crd had the f37 recall with a new TC, when the recall work was done they forgot to do the loctite. At the time it was going on a couple others had the same issue.