Power Steering Fluid problems of the 2007 Toyota Sienna

In winter when the temperature fall to 30 and when steering get a load squeaking noise and taken to the dealer (first winter) winter and they informed that it is not re-creatable. Many times the problem was reported to the dealer and no action was taken because it is not re-creatable. After warranty period expired I was asked to change the steering fluid to fix it. I did not since it was not due to usage/handling the vehicle and it is due to fault in manufacture. Next year we were informed that it is a safety issue and I need to change the steering fluid. I mentioned to the dealer should inform the Toyota head office on this but nothing was document nor it was followed up by the local dealer. I am leaning towards the warranty coverage rather the consumer to pay because steering fluids should perform as it supposed to and do the job it supposed to. Any failure due to steering fluid and any damage caused will be Toyota responsibility. It is 11 years passed and will continue to drive and hoping this will be fixed at any point of time before the crash occurs due to failure of the steering fluid leakage. This vehicle is driven in frankfort ky.