OK, yesterday I put a new water pump on my 1996 F250 7.3 PowerStroke with no problems. Let it run, no leaks and all is well. Then I drive it about 30 miles and the trans starts shifting extra hard out of the clear blue.(automatic) Now the OD off light on the gear selector is flashing on and off all of the time and still shifting hard. It still shifts through all the gears and goes into OD at correct speed, just feels like a neck snapping shift. WHAT IS WRONG????? Looking for any and all the help I can get to figure this out. Thanks in advance!

 

You need to take it to a transmission shop and get the trouble codes that will be stored read. The parts stores that read codes for free won`t be able to do it.

 

Hard shifting often means teh computer is boosting pressure to stop slippage that it detected. The faslhing OD light means a code was stored.

Get the code read. Probably a tranny shop is the best bet since many of the cheap readers don't read tranny codes.

As to why this started after a pump change. Hard to say. Did you check fluid for color and smell? Red and chemically is good. Brown/black/pink and burnt is bad.

Maybe you overheated things in the tarnny cooler? kinked a tranny line? Maybe you knocked some sensor wire loose? I don't know this engine and tranny but I don't think there are any control wires affecting the tranny at the front of the engine, but like I said, don't know.

Good Luck,

Jim Henderson

 

What gave you that idea?


The transmission has no memory and all codes are stored in the PCM Computer.

 

^^^


I am not sure if that code reader will read a 96 and later OBD-II system, it says 81 to 95 on the front, that's OBD-I.

 

I did not notice it was a diesel. You would need a OBDII code reader to read the codes.

 

Thanks everyone for the suggestions. I talked to a mechanic this afternoon that I trust a great deal and he said that these year model Ford trucks very frequently would get a short in the wiring in the steering column and cause this. He said to just take the plastic covers off of the steering column, find the two wires that go into the shift lever and follow them out. He said that the majority of the time you will find one wire rubbed bare and just need to tape it up. Hope so! I can't afford any expensive repairs right now!! Thanks again and maybe the info I learned might help out someone else as well.

 

When those wires fail the button and the light quit working, yours is flashing, the wires are good.

Get the codes read it just might be a speed sensor or something else minor causing all your problems. Most trans shops will scan it for free if you just ask and say please

 

I tend to agree with you JK080, I checked the wires this morning and they looked fine. I disconnected the battery for a couple of minutes to clear codes and see what happened. So far so good. I drove it about 8 miles and it is perfect so far. I am going to give it a little bit longer test drive later today and see if it may have just been a fluke or something that caused all of this. Thanks again and I'll keep you posted if this fixed it.

 

Are your speedo and odometer working? I had this same problem and it turned out that the fuse(speedo) had blown causing the trans to shift with line pressure rather than the soleniods.

 

The speedometer and odometer are both working. I'm still not sure what caused it but it has not happened again since I disconnected the battery long enough to clear the codes. I have driven it maybe 50 or 60 miles since then with no issues. I was accelerating harder than ususal when the problem first happened so maybe I just freaked out the computer for a minute! haha! Thanks for the info!

 

Some of the readers, like the free readings at Autozone etc, don't give you all the brand specific codes, or their code book doesn't list what does pop out. This was a common problem when I had to use the freebies, but I have my own reader now, too bad it doesn't read codes for my lincoln Canbus, arr, got to get another reader.

So you need a reader that can handle those codes, which a tranny shop usually has.

And there are at least three types out there, OBD I and OBD II and those that can read the Canbus codes usually off a OBD II type connector.

Just my experience,

Jim Henderson