Some of the people that work on these 6.0 diesels are incredible with their knowledge. I try ti diagnose best I can but ask any questions you might have. For some strange reason I was also leaking trany fluid where the cooler connects to a new radiator. I tightened that fitting and now have a small leak at the pan . Just in case something has to do with pressure lock. Like I said some of you guys can pick up on something completely off the wall and say exactly what’s wrong and where to look. I changed my oil, oil filter cap to billet that accepts motorcraft filter. When I started the truck it barely cranked up with fully charged batteries. oil pressure dropped to nothing so I turned it off instantly. Ever since then the dash lights flash and truck just clicks clicks like if it had dead batteries. coincidentally at the same time all remotes to my alarm stopped working autostart obviously doesn’t work. I see no loose connections other then the after market alarm that has been on there for 10 years. I was thinking of ripping off all that alarm remote start stuff. Unless someone can point me in a different direction. I just ordered a DTC code reader. I also have electrical issues with a 2003 expedition.
Carefully look at the battery cables, especially where they connect to the batteries
Ford battery cables sadly aren’t the best, and when you clean up all the corrosion, you sometimes find that the cables are literally cracked all the way through
Some Fords also use a separate starter-type of solenoid, in the engine bay, usually located on the same side of the engine bay as the battery. If you have one of those, make sure all the connections are tight. I’ve seen them loosen over time, which causes all sorts of electrical problems, up to and including no starts and stalls.
Sure, they’re fully charged, but are they any good . . . ?
How old are the batteries?
do they even pass a load test?
if the engine stalls, or is on the verge of stalling, your engine oil pressure will also be lower than normal
This trans fluid cooler . . . is it factory or aftermarket?
The connection you’re referring to is a screw type, correct . . . not a quick-connect?
as for the leak at the pan, is it seeping out from under the gasket, or is the pan itself rusted through?
are all the pan bolts tight?
are you still using the original Ford reusable trans pan gasket . . . they’re actually better than the cheapo rubber gaskets that typically come with a new aftermarket filter kit
5R110W auto trans, I presume?