Does the truck have a "chip" or programmer? That could make a huge difference depending on the program.

 

Did you ever figure this out? I have pretty much the same issues, but don't have a fix!

 

no chip no programmer. all stock always has been. aside from the plow of course. havent found any electrical faults. brought it to the stealership to have their diesel specialist have a look and he couldnt find anything either. so i went ahead and pulled the transmission. pulled it apart and checked every lip seal in the trans as per the ford dealerships advice. and no surprise found no issues. generally intermittent failures arent sealing issues. thats not to say they cant be but usually arent. so after some more reading i saw a few people have had problems with their pumps. so i pulled that apart and checked it. i found a couple valves that were questionable but nothing stuck. so i pulled them out and saw just a little scoring in the bores. so i polished them and checked the spools for scratching or wear. i did not see any so i cleaned them and the bores thoroughly. i reassembled the transmission today, its being installed as im typing this. we will see if that has had any effect.

now for some more diagnostic info.
when the trans attempts to start in 5th from a stop the line pressure on my gauge shows 14-20 psi. way low.
at first start trans pressures range between 170-200 psi
once warm they drop to 70-100 psi
on deceleration the pressure usually hangs 30-60 however has dropped as low as 14 psi
the highest its gotten is 320 psi on hard accel when cold or braketorquing.
the gauge and scanner rarely match commanded and actual pressures.
sometimes the gauge is steady and others its almost vibrating.
there is a drop in pressure by about 15-20psi before a shift
once warm its cruising at about 60 psi
when it goes into failsafe mode and tow haul flashes the line pressure increases and stays between 120-175psi.

thats the update. dont worry guys im staying in this till theres a fix and will continue to post up my findings.

 

Fixed update!!!

Okay so my fix came down to the valves in the pump. Polishing them made the trans feel brand new. Got rid of the strange issues it seems. Ive put a good few miles on to make sure the problem doesn't come back and all seems to be well. If it comes back ill post up but the pump valves seemed to have done it.