well u probably wont find anything with taking the pan off. all it is, is a valve body with solenoids for the shifts of 1-2 2-3 3-4. the problem would be in the transmission case. this sounds like the clutch packs are slipping, there might be an internal leak for the clutch packs to engage. bring it in to ford or a tranny shop, preferably ford cuz they see trannys specifically from fords not like a tranny shop where they might not of seen the same tranny before.