Re: 2005 6spd loud squeak coming from under the car.
That does not tell us enough. You've got to ask yourself, "what seems to make it happen?"
That is, does it squeak when the suspension moves (that is, car goes over uneven ground)? (This would imply suspension parts are at fault - springs, shocks, etc.)
Or does it squeak anytime the car is moving? (THis would imply that drive line parts are at fault - flex discs, bearings.)