I have not done mine yet, but when it gets to 30k I will, I do all my own service, what kills transmission fluid is it looses it's additives over time, changing only 30% of the fluid with a pan drain is a waist of time, ( that is how it was done in the 50's-80's, old school), all the fluid has to be replaced, doing the trans cooler line exchange is not a major task, and done correctly will do no harm, mine has an oversize pan with a drain plug, I will drain the pan, make a note of how much fluid there is, replace both filters, re install the pan, and replace that fluid with new, disconnect the cooler line run the engine and when I am almost to the amount of fluid the pan holds shut it down and refill, doing this about 4 times will have all the old fluid replaced, I did this a couple of times in my 05, and have done this on other vehicles I own, it is a great way to keep the trans healthy