I installed the PA aftermarket aluminum pan on the bottom of the 5R55S. It comes with a locking style dipstick, that resides next to the firewall on the pass side. The dipstick opening is large enough to add ATF if required. Drain plug on the bottom of the new pan.....which also holds an extra 4 qts of ATF. I used 100% synthetic ATF. Also installed a B+M tranny cooler in series with the oem Ford tranny cooler.