After I install every thing and drive it around for a while do I have to change the transmission fluid? If so how long after the install do I have to do this 500 miles or so? Also after I drain the pan I wanted to put in that redline synthetic fluid but will it be ok to mix that with the regular atf fluid that would still be inside of the torque converter. I dont want to put in the synthetic to start with and then have to drain it out right away, because that would be alittle bit too expensive.