Keeping your fluids clean and contaminate free is a major aspect of vehicle maintenance, and failure to keep them clean will always result in bigger problems.
A loud whining noise while turning left and right is usually a power steering problem and often times flushing out the fluid or even adding fluid will solve the problem. Left alone and your looking at changing out your Power Steering Pump or even a very costly Rack & Pinion.
Poor Transmission Shifts, Hard Shifts, and a loss of power are all signs of your Transmission Fluid needing to be changed. On most four cylinder automatic vehicles it just requires draining the fluid and adding new. Bigger engine vehicles, vehicles with four wheel drive, and lots of others also have Transmission Filter that needs to be changed out as well. This usually means removing the bottom part of the Transmission, changing the Filter, replacing the Transmission Pan Gasket and resealing the transmission. A Transmission service like this normally runs between $159.95 and $199.95 Depending on how many quarts of fluid the vehicle needs.