Hi, I have a 1996 Ford 450 superduty 7.3L powerstroke. The problem is the turbo works fine for about 10 miles then it completely cuts out, ie: the truck still runs but very rough and ofcourse as soon as I start up a slight incline it will drop like 20mph then pick up speed on the downslope. I am a good mechanic but I DO NOT know much about diesel and turbos and this is my first one owned. I pulled off the air intake to the turbo it spins freely, it does not have any play in n out or up and down also I saw it spinning at idle. Anyone have ideas? History of truck it is a stake body used to haul HVAC units, has 145000 miles and I ran some additive in the fuel for stiction? I guess. oil change under 1000 mi ago, new air and fuel filter. it is being used to haul some trash for a restaurant 1 time a day for about 20 min.