Re: 545fre trans filter change
I didn´t do it on a WK, but on my WJ 5-45RFE. It is a little bita dirty job, since there is no drain plug so that you can drain the pan before removal. You will need a large recipient to catch the old fluid. Remember that you will only change 2/3 of all fluid in this way, because the torque converter will still have a few liters in it.
For the spin-on filter you will probably need a filter tool, on mine it was impossible to remove by hand.
For the oval inlet filter you need to install the seal first in the inlet of the pump and take care that it is flush (use the butt end of a hammer or alike). Thereafter you can install the filter itself. Trying to install the filter with the seal on it, will probably result in a detaching filter lateron and a tranny which losses its gears and a change on internal damage.
Not sure on the WK, but on the WJ the tranny pan is sealed with RTV sealant from the factory. There are gaskets available, which make the work easier (especially when removing the old RTV), but my experience is not so good (started
leaking after a while), so i only use RTV now.