Hey there folks. Hoping I can get some input on a trans issue...

Back story - trying to help my elderly father with his 2003, 7.3, 160k miles, PHP hydra tuner.

Issues - O/D death light flashing. Been going on a couple months now, however drove and shifted great. No different than before. No overheating (6.0 cooler as well), no slipping, nice firm shifts like it always had.

Until today, it was fine running to Home Depot, then we left and it held first gear till I let off the throttle. Then it started to randomly shift around and go into neutral till I let off the throttle again and played with the O/D button. Then started shifting fine again.

Our mechanic pulled the tranny codes for him, here's what we got...
P0733 - #3 Incorrect Ratio
P0741 - TCC Slip
P0743 - TCC Circuit

What I've done - tried to research the issue and everything seems to point to electrical. I got up under there and pulled ever plug I could find to verify they were clean and dry, and dielectric'd them.Anyone have any input? Time for a new trans or something (hopefully) simple like a speed sensor?Thank you guys for any help and input!

 

I recommend taking it to someone that can diagnose the P0743 electrical fault. Pulling connectors and putting grease is fun, but it doesn't do anything towards finding and fixing an electrical problem. You need a DVOM, a wiring diagram, and the ability to measure continuity from one end of a wire to the other end, and to ground and to power.

 

That will be the next step. Really just grasping at straws hoping someone had the same issue. Since it's Sunday and I can't take it in till tomorrow. Kinda funny, on the PS forum, the very first post is a guy telling his issues and they are identical to mine. General consensus was he needed to pull the codes, so I was kinda a step a head and wondering what people had to say.

 

Many of us have access to the wiring diagrams from the Ford Service Manual if you have a multimeter and want to investigate the issue yourself. If you have a trusted shop, that may be your best bet though if you don't have the time or tools to dig in to it.

Just an example of a 4R100 wiring issue a short while ago in the link below.

https://www.ford-trucks.com/forums/1...y-problem.html

Let us know if we can be if help to you going forward.