I had the same issue come right after I bought the truck, I did a complete service and have no trouble afterwards and have put another 25000 miles on it. I service the trans every 15000. Try that first. I found the filter was never changed from day one and was starving the trans for oil. Also change the return filter by the cooler if it was installed.

 

I had a very abrupt 2-3 shift after installing a DP 4 pos chip in my '01. Took it to ford who found no codes and told me"We drained it, flushed it, and put some conditioner in it. That may or may not help. Otherwise you'll have to rebuild it." A very good tranny shop told me their expensive scanner showed a 2-3 shifting error. Probably have to rebuild it. Drive it til you can't stand it or have 2 grand to spare. Then I called Brian's Truck Shop. They sent me a valve body that solved it completely. I still tend to heat up a little too much when driven hard but that's an issue for later. This valve body works like a dream and is an easy 2 hour install.

 

I have a scanner and all I got from it was PO401 which is EGR flow insufficient.

 

If the OD light was flashing there was at least one code that was from the transmission. If the OD light was flashing and you got was a P0401 then you don't have the right scanner.

 

What I have found on my 98 Ranger is that once I get to 50 or 60 mph the overdrive shuts itself off and then when I slow down, shifting is very harsh. I read through the repair manual and think I found the problem.....I think my shift cable needs adjusted. I tested this theory by holding my gear shift up as far as I could while I got it up to speed. I got the truck up to 75mph on the highway in this fashion without o/d shutting off. worked normally. Once I got off the highway, let go of the gear shift and got up to 50mph, o/d light started blinking again. I think just an adjustment of the shift cable will solve my issue. will let you know if this works for me.

 

What code was set when the OD light was blinking? The code will stay in memory for a long time after it stops blinking.

Without the code all you are doing is guessing. At least this guess doesn't cost any money.

 

I don't have correct scanner for the tranny codes. All engine codes I get are PO401 which is ERG flow insufficient...
changing that now

 

I have a 2001 250 SD 7.3 and had the same problem in July '06. The truck is now sporting a Ford remanufactured transmission. Problem solved.

RP

 

Well, I did get the check engine light to disappear and also cleared the PO401 code after changing the ERG valve. Just finished this job and slowly am clearing all codes and issues. last but not least is the o/d and I am hoping to try to adjust the shift cable this weekend. Will post if this solves my issue.

 

I Have A 2003 550 Diesel And Same Light Came On It Was My Solinoid Valve Body In Trans About 500.00 Can.

 

I Have A 04 350 Doing The Same Thing. It Seems Like It Is Stuck In 3rd. Help

 

I am starting to think that it is just the cable shift adjustment next to tranny pan. i have not had a chance to make the change but will let you know if this works for me.

 

I had the same thing happen on my '97 7.3 and it was the shifting pump in the tranny. My local tranny shop had to replace it several times because they couldn't get one to hold up to the build they put in it.

 

i have had no trouble since mine was replaced about a year+half ago over 10000 klms since then and i use my truck for work daily.drain pan every three months.itwas a threepac soliniod unit replaced

 

Maybe you should post that in the "automatic" vs. "stick" thread