hello guys i have a 2002 ford f350 7.3 diesel automatic transmission with bully chip 4wd, i have two problems that are probably related, when i put my truck in reverse it backs up but has no power, even if i press on the pedal and bring to 3000 rpm it doesnt backup faster, my second problem is that it has a hard time going from 3rd to 4th gear, it redlines for a while and finally switches to 4th gear, my OD LIGHT FLASHES, could you tell me what are the verifications to make to be able to find the part that is causing this in my transmission?

 

Normally I tell people to get the codes read. The flashing OD light means codes have been stored. In this case I think it's a waste of money. I'm 99% sure I know what's wrong. This trans is toast and needs to be rebuilt or replaced. Sorry.

 

i flushed my transmission oil and there was a bit of metal particles on the magnet, the truck has 320,000km and i think that the oil hasnt been changed for a long time, is it possible that the oil was saturated because when the transmission finally shifts in 4th gear it works perfectly fine, got it scanned an hour ago and there were two codes, one is excessive slipping between 3rd and 4th and the other had to do with the torsion clutch converter

 

the code was P0741

 

As Merk said its time.... At 320km (~200K miles) you have more or less met the life expectancy of a medium duty automatic transmission, especially one which has not had the benefit of regular oil and filter services (speculation only).
That should be performed every ~50-60km depending on your driving habits. With regular service you may reach ~500km so roughly a third to two thirds more life with regular service.