what causes a whining noise in a car
One of the prime reasons for whining noise may be friction caused in the car transmission mechanism. The reasons for this might be worn out gears and low transmission fluid levels. You could check whether the problem is in the transmission in the following way. Accelerate the car to speeds at which the whining noise is the loudest, switch to neutral gear and kill the engine. If the noise still persists, then the problem lies somewhere in the drivetrain or transmission.
#2. The sound you are probably hearing is straight-cut transmission. The whining noise is caused by the teeth of the gears slamming together. Its nothing to worry about and the reason why it's not audible in most road cars is that they use helical gears to keep the transmission whine to a minimum.
If the whining noise while accelerating is loudest while taking a turn, the problem may lie in the power steering assembly. The main reason for the whining might be a loose belt, that runs over the power steering pump's pulley. Getting the belt tightened and the whole assembly realigned, might solve your problem.
This is also why cars in reverse make that whining sound, reverse gears are often straight. If you get a car up to some speed in reverse then dip the clutch the whine will continue until the car stops because it's the transmission.