transmission or engine problem?

i started the car up today to take out of garage and clean it up. it ran fine when i pulled it out but when i started back up to put back in the garage it sounded like a knock so i shut it off. i looked at the scanmaster and it looked fine... so i started it back up and was trying to listen for the sound but it sounds more like a rattling sound than anything. so i looked under the car and didnt see nothing hitting. but i noticed when i put the car in reverse and drive the sound goes away.

not to sure what it could be .. i pulled valve covers off and everything looks fine.

any suggestions?

try checking converter bolts,or flywheel bolts,also could have cracked flywheel

i have the same exact problem i looked at the flywheel i couldnt see anything obvioius. did youi ever come to a conclusion i would greatly appriciate an answer

I would go with broken flywheel at crank bolts. have to pull trans and converter to see it. get a sfi unit from one of the vendors if its cracked. I replaced one in my friends car and 3 weeks later the stock one I put in it broke again.