It has internal parts that have failed, it has to do with or is wha's called a low/reverse band, drive it to a repair shop and get it fixed. It is not a fuse, solenoid or wire and will not have codes! You do not have engine braking in manual low either! There it is, i wish it was an easier fix!
No, if you will do this test EXACTLY like i ask you to, we can tell what it may need to get you back on the road. Here goes: driving at 20 mph, no more than that, with trans. in drive, pull the shifter stright into LOW GEAR, does the truck slow down on it's own? In other words does the engine hold the truck back just like down shifting a stick shift? Or does it just keep rolling free? That is what i need to know next! Remember from drive right to LOW gear for the test, not from drive to the next lower gear but down shift it to LOW GEAR. Do you understand?
Okay.. You mean engine brake,right? What are the circumstances,if it runs freely or it has engine brake? Right now i have found a 20A fuse that keeps blowing out.. It is on the passenger side kick panel.. It doesn't say name of the fuse..
I can't drive it right now.. If its not a whole transmission,what else i should check.. Because the time i drove it engine brake was working but i did not tried from D - L.,i know you have a lots of experience of fords as i saw your comments.. Buddy i need whole info about this issue not one by one.. You might need my help in the future for domestic models not US..