Transmission fluid is a very important for the operation of your vehicle and engine fluid can lose effectiveness. It is necessary for applying the clutch, lubricating and cooling the internal parts. Over time transmission fluid to loses effectiveness, due to heat. If you notice a change in your shifting or the acceleration of your vehicle, this may indicate a problem with the transmission. Another indicator that you may need a transmission repair is if your engine sounds as though it is racing, while driving at a low speed.