05explorerXLT, if there is a part of your driveway or some other place you can work where there is a slope, you might try filling with the truck facing downhill a bit (safely of course, strongly applied parking brake, good wheel chocks). I was surprised at how much more fluid stayed in this way as opposed to what seemed to be when on a level surface. Jacking up the driver's side a bit helps a little too (and eases crawling underneath).
The brake bleeder tubing I use is fits the center hole in the drain plug almost snugly, so it holds fluid in as it fills. Of course, it goes in under constant pressure from the weed sprayer, which I think is easier than pump/fill/pump/fill.......
FWIW, the whole story is this: got the truck not long ago with a thumpy 2-3 shift and torque converter shudder (no flashing od light though). Installed a set of the o-ringed servos, readjusted the bands (on the tighter side), and the last step is what we are discussing now -I drained and refilled using mercon V and Lubegard (friction modifier, highly recommended). The refill was trickier than I thought and it wasn't till I took the step to possibly overfill did the tranny become 100% (good shifts cold or hot, even after hard stop, no more torque converter shudder).
Best of luck!