chiken
A clunking noise, when you put your car into gear, is most likely caused by a bad u-joint. A problem in the transmission can also cause the noise.
A car that is in good running condition should not make a clunking noise. If a person pushes the gas and brake pedal at the same time causing a car to make a clunking noise, that is an indication of stain on the motor.
Could be many things, ball joints usually make clunking noises (usually one when turning and one when turning the wheel from turning), cv joints usually make a clicking noise and vibrate under load. Have it checked out, les schwab will do it for free (check it).
One clunk when accelerating (but now repeated clunks) and another when braking can be caused by broken motor mounts.
mine needed power steering fluid
the car may be low on power steering fluid
If there is a clunking noise on a 1991 Firebird Formula 5.0 when going below 30 mph, and the clunking noise does not happen when the clutch is depressed, it is probably a problem with the flywheel. The flywheel moves freely when the clutch is depressed. When the clutch is not depressed, it could be that something is rubbing on the flywheel, like the clutch plate.
could be your wheel bearings
The front wheel bearing is bad. The sound will be more pronounced when turning one way but not the other. The bad bearing is on the side of the car opposite the turning since more weight is on that side of the car when turning.
could be your crank shaft
Worn out front shocks and struts will make a clunking noise when you go over small box. The strut may actually allows the tire to hit the fender well.