i have a 2000 v6 mustang 3.8 standard 5 speed transmission and i have a rattling happening but you cant hear it out side of the car but when your inside of the car you can hear it rattle but i didnt have this problem untill i changed my clutch and fly wheel i changed both of them brand new when i got it back it was rattling. ever since i been trying too fix it so i changed the motor mounts,transmission mounts, sparkplugs n wires the only thing left i think i should change is the harmonic balancer, or transmission because b4 i changed my clutch n flywheel my transmission would lock up meaning it wouldnt go into any gears but i would force it into gears but when i changed my clutch i tightend some bolt on the transmission that i guess holds all the gears together n my transmission been working fine but have this rattling problem what could it be.. sumeone please help me i want to fix this problem intead of fixing things that aint the problem ....some more info about it when i turn it on it doesnt rattle but when i rev my engine it rattles and when i accelerate it rattles so basically when it reaches 2000 rpms to 3.5 rpms it rattles n no it isnt the exhaust pipes or anything on the cats cover cuz u would hear something under the car but i dont...p.s. i have bbk headers,cold air intake and dual exhaust x pipes and a spacer does anyone kno my horsepower with all them parts....

 

Does it do it with clutch in or out or either? im thinking throw out bearing but someone more versed in trans stuff would know better.

 

nope i changed that when i changed the clutch

 

and it doesnt rattle untill i start driving or rev it so basically when i bring the rpms up it rattles when in nuetral its fine