Re: Milky Transmisison Fluid -- 05 5.7
I'm almost sure they have to drop the tranny to get to the dipstick seal. I rebuild my transmission last year and can tell you that this seal was not that easy to get in place. Or at least its not difficult to get the seal on the dipstick tube, but to get it then aligned and into the transmission was quite a struggle. I had to do it on my own, so probably an extra pair of hands would have helped.
It seems that there was a service bulletin regarding this water contamination via the dipstick tube. Have a look for it, you never know if guarantee will cover it.