I will be flushing my transmission fluid in my 2000 f350 6.8 4R100 in the next few days as my oil/parts come in.

I have a leaking stock oil to air cooler. It is dripping out pretty good and I have no real idea how much fluid was lost. Truck drove into my shop at home no problem but with a slightly different 'engagement'.

I have a new mishimoto cooler, filter and two cases of motorcraft mercon V on its way.

My question is what is my best way to go about repairing and flushing this? My gut says to fill it up a bit before I flush it. But is that nescessary? Or should I just get set up with Mark K's flush procedure and not waste any oil trying to fill it back up? Drop the pan, change the filter and top up with what comes out of the pan and start flushing? I can flush before removing the old cooler as it appears to just drip out at a fairly steady rate.

Thanks for any thoughts on this and thanks for the write up from Mark K and the numerous people who have posted threads on this procedure before. I'm quite clear on how to do the flush, just mostly uncertain on whether I should refill the transmission to the proper level and warm it up before starting the flush? And if that is the best way to go about it should I just change the cooler first? I'd prefer to keep the old fluid out of the new cooler but besides this new leak which has prompted this whole repair and maintenance I've had zero issues from the transmission.