I agree the torque converter thing is suspect.
One thing about the Ford Superduty oil gauge though: It is my understanding that the gauge is jigged (by Ford) so it reads in the middle no matter what (unless the pressure goes to zero). It is certainly that way on my '99 F350 SD diesel. In other words it is an idiot light. The reason they did this (according to Ford mythology) is that when an engine idles the pressure can go down very low, 5-10 lbs, even though everything is fine. This caused customer warrantee complaints. So they "fixed" it. There is a mod you can do (involves cutting a resistor if I recall behind the gauge panel - Google it) that restores the gauge to proper operation. If the gauge is really a gauge, it will read low when the engine is warm and idling. Mine never moves, except for when you start or stop the engine.