I've had it with this 904, about to give up!

I did re-do the pump. I'll be honest I'm not sure how to check them, other than looking at the parts for excessive wear. The trans was in great shape when I rebuilt it with 79k miles, all original I believe but had been sitting out of the car so long and not driven since '79 that I went ahead and re-did the whole thing with red clutches and all the goodies. The rings in the kit I used were steel.

I will look at the FSM and see if I can manage a pressure test. I guess re-doing the pump isn't so bad. Aside from pulling the damn transmission :/