Is there (tranny pan) somethink magnetic plate which attract "metal chaff"? I think that I put transmission drain plug kit and I think that is it have to be magnetic? Sorry my bad english =)
Doesn't have to be magnetic, but it wouldn't hurt. Watch your ground clearance, and clearance inside the pan when you install any drain plug kit.
A 400 doesn't have big ground clearance; the 68 & later are 1/4" lower from the newer filter style. I WOULD NOT put a drain on the bottom; in a rear surface works for me. That will keep a road hazard from wrecking it. A side drain won't get 100% of the fluid, doesn't matter. The idea is to drain fluid well below the top of the pan, so it can be removed (to change the filter) without fluid spilling all over. Bolt in drains broke for me. So I brazed in some 1/4" steel, drill & tapped a pipe thread. Bruce Roe