Yesterday was my turn with the HPOP (Stuck in CA) today my friend's trans is giving us trouble. It's also a 2003 7.3 4R100. OD light started blinking and now it won't shift into OD. If the OD is shut off it keeps locking and unlocking the torque converter in 3rd gear, If the OD is on it will shift into 3rd and stay there. Drove it about 100 miles that way and it's still running. Still won't shift into OD however. Any ideas?
If it will keep running, we are planning to light about 30 miles north of Phoenix, I think Strictly Diesel is in Phoenix, maybe they can help.

 

My idea is to have the codes read so that you know what's wrong. Without the codes all anyone can do is guess.

 

Thanks for the reply Mark, I wrote that last night after a stressful day on the road before I had a chance to think it through. I know yo are right and today we will be looking for somebody to read the codes for us.

 

Good! That's the best way to find out what's wrong.

 

Update: we discovered that the truck has a Superchip tuner in the console and has been programmed with a tow tune. I hooked up the tuner and took it back to stock. The result was encouraging, truck shifted fine and we made it to our destination, with only one glitch, the trans overheated. my friend (Bob) backed his trailer into the assigned site and went to park the truck and the trans is dead, no reverse and slipping in forward gears. We will be looking for a trans shop in the Phoenix area. We'll be here for a month.