I did lube the front and rear seals before putting the converter on, and the driveshaft yoke. I don't think the front leak is coming from the seal (as far as I can see). I do get a leak from the rear seal...and I think that perhaps that driveshaft yoke has a groove worn in it. I'll be replacing that at some point.

I found a stock photo online and marked it up where the leak seems to be coming from. It seems to be coming from where the pump mates to the transmission housing (where the black meets the silver in the picture). I don't know if the trans in the picture is actually a TH350...but it shows the area well enough.

Is it easy to pull the pump and replace the seal? Or does that open up a whole can of worms that I don't want to get into?