I am having a similar problem on my parents 95. Was on the highway doing bout 140 KM/H (~87 MPH) and some points higher, for a very short time hit 200 KM/H (~124 MPH), probably 140-160 KM/P (~87-100 MPH) range for 99.9% of the time on the highway while I was driving. I drove about the last 75%, my sister drove the first 25% and she drove about the 120-130 KM/P (~75-80 MPH) range. The o/d light started flashing about 40 minutes from home, was driving for about 3.5 hours and did stop for 20 minutes half way through.
I pulled the codes and got 628 - Excessive converter clutch slippage. Talked with my buddy who owns a sho and works at a ford dealer as a mechanic. Their tranny guy likes SHOs, doesnt own one but does know about them and said it most likely the oil pump shaft bearing is shot and wearing out the converter clutch seals. Also the tranny is shifting hard do to the trans failsafe mode, it upps the EPC (electronic pressure control) solenoid to max, so instead of the clutches and bands seeing 50 psi in drive, it sees 90 psi, causing the harsh engagement, because of the converter slippage.
So time for a rebuild but for the time being I do have another tranys out of another 95 that I will give to my parents to use till they can get a rebuild done.
The trany does have 245,000 KM (152,*** miles) on it and had a flush and something replaced about 40,000 KM (24,*** miles) ago (Cant remember what it was will have to look at the bill, i do want to say solenoid
).
