I have a 03 350/auto/diesel and the other night i noticed the o/d botton began to flash and was shifting real hard and it didnt seem to want to go into o/d. So after i stopped and turned it off and back on it stopped flashing but would hang in gear and still not want to go into o/d. The next morning i went to leave my house and i had no reverse but drive and all the other gears worked. No change in temp of tranny and no slipping converter. What do yall think it could be...Converter? Sylenoid? Speed sensor?....TIA.....

The truck has 22.5 acloas and 385/65/22.5 tires if this helps......

Edit: When im driving i can turn o/d off and it will down gear. But when its back on it seem to be at a higher RPM then normal.

Well since you said o/d your trans is the 4R100 behind the 7.3L diesel? 2003 was the launch of the 6.0L

You should have a code, the flashing button is to let you know. Any detected changes from input to output across the trans will alert you. Just my guess....selinoid and/or wiring in the trans becomes brittle.

Yes, it is the 7.3. I really hope it isnt nothing major. Would it be the converter even though drive, 1 & 2 still work? No slipping what so ever and no change in temp...TIA...

It is time to hok up to the dealers diagnostics and see what is going on. You should have a code to point you in the right direction of what happened.

Sounds like a speed sensor going bad. Need codes.
mike

What your experiencing is a prelude to total tranny failure. Reverse is usually the first to go in the 4r100. A sign is also if you are in rev. and you hit the throttle a bit and it shutters (vibrates real bad) it's toast. I've had 2 and these are the symptoms they both showed before they died.

I took it back to where i bought it. They hooked it up and not to sure what else they did but its back to normal. Shifts and goes into reverse just fine. Im just going to baby it even more from dead stops to help roll the tires i have on it....Thank yall....

I dont know if its the same thing, but on my dads on 93 powerstroke the o/d button would flash on/off and would be very hard into OD. Did it 2-3 times over 275k or 4 yrs.
Each time that o/d switch had to be replaced, and then all was fine. Hope thats all it was for you.

It sounds like a speed sensor or a bad or loose connection . If you have any other problems you can call
John Woods 760-356-9421 he knows the ford tranys !!!
Roger