noise at transmission/engine coupling? clacking, not ticking

[18cherokee]

hi, i have developed a noise that seems to be coming from the trans or back of engine block near the firewall - it is evident when i take my foot off the gas & roll to stoplights etc.

its like a very slight clacking noise - not a constant ticking lifter or exhaust leak noise.

i have tested it a few times, when i hear the noise i very gently put my foot on the gas & it seems to go away. back it off again & it comes back.

it isnt usually noticeable at idle/stop, unless the engine is hotter ie from a long drive at speed on the freeway.

normal temp = noise when coming to s stop, not usually when stopped.
hot temp = noticeable at idle until engine cools down

help
thanks

[Carnuck]

Check bellhousing bolts, including the starter ones.

[gsmikie]

cracked flexplate if you un bolt the converter and slide it back and tap the flexplate with a wrench if it rings it is not cracked if it sounds like a thud it is cracked

[18cherokee]

i've had a cracked flex-plate before - this noise is so much more subtle than that, nothing like it really - my mechanic is looking over it now, thanks for the input though