Whistling/hissing sound when in Park or Reverse ONLY. 2003 4.4

[1stE53]

Originally Posted by m5james

As long as a shop catches all the transmission fluid, checking the filter should be a fairly easy job with a lift. I've done it on both a lift and having the car about 1ft off the ground, shouldn't take more than an hour to check. Replacing the fluid opens a whole ball of wax that people will debate left and right, but replacing isn't part of the debate if that's in fact your problem.

I have read hours on this but just wanted to ask you if you replaced your transmission fluid? If so, at what mileage?