the car kinda always made some low ratling noise on deceleration but it got worse once i build the engine. i got pistons rods and no balance shafts... @ first i thought it was my act beacuse it kept locking me out of gears. i got a quarter master and noise still there.

it makes the noise going around 3k rpm while parked and when runing it makes it as soon as i let off the throtle once i set one pound on the gas it stops... its very loud and vibrating.......
i cheked under the car and once i hit the 3k rpm the driveshaft starts vibrating like hell and making noise ...... changed the entire driveshft and the noise and vib continues
iam all out of ideas what is making the driveshaft vibrate like that?

any you guys had that prob? please .. need to get it fix
any help will be appreciated