2003 ford windstar loosing power

My 03 windstar makes a ratchiting sound and looses power upon excelleration and up hill driving both front axels have been replaced

Is it like ball bearings in a can? I suggest this is the valve clattering, and the knock sensor is dropping the timing to try and prevent it. However, all you get is a loss of power. You may need a mechanic to look at this further.

the sound is like a high speed ratchiting or like a drive belt with teeth slppping over a pully