So now I have a new issue with my 2000 Dodge Dakota ( 4,7 w/45RFE automatic). I'm driving down the street when without any warning it just stopped driving itself. No forward or reverse. I rolled off to the side of the street and turned it off. After checking the fluid ( about a 1/2 quart low) I started it up and it drove fine. I went straight to a parts store and added fluid. It went about another three miles and repeated the problem. This time, even after sitting for a bit it still would drive itself. I had it towed home and it has been parked about a week while I researched what the issue might be.
.. I've decided to flush the fluid as it's kind of old and it's seriously aerated . I've disconnected the lines on the cooler and if my research is correct I should be able to start the motor, put it in neutral and the old fluid should pump out.
But there's the issue, it doesn't. Drive, reverse or neutral and no fluid flow. Is this an indication of a failed fluid pump or what else could be the issue?

 

Yes if there is no fluid coming out in drive, then the pump has likely failed.

I am not sure, does the 545RFE have a pump clutch? I believe most newer trans do, to shut the pump off in park and neutral. I could see that going south if equipped?