ticking or knocking noise

[svxin]

ok just put a used motor in my svx all new gaskets and seals in motor new flex plate, after about 4 weeks now its making a pretty loud ticking sometimes knocking noise this only happens at idle up to 2,000 rpms then it seems to go away but i dont know because the car is so loud, the sound seems to be comming from between the motor and trans so i guess its my flex plate but its brand new anyone have an awnser or had a simmiler problem i am sure its not the motor because the sound isnt there untill i put it in gear then it starts ticking and does so after i put it back into park,im hopping this is simple