42RH advice needed

What am I looking for when I drop the pan? I replaced the pan with a deeper aluminium unit when the transmission was installed less than 100 miles ago. I replaced the filter and fitted the Sonnax valves that allow the TC to fill in Park.
Remaining fluid in the trans when I got it was dark red not brown and no significant amounts of friction material in the pan. Also not much metal on the magnet.
The Sonax valves may not have been installed properly or were defective. Show us some pics and the instructions. I assume u changed the manual valve and what else? Kim