Hey yall, just bought an 05 f150 off my boss. He replaced the trans with one out of a donor truck and put in a new torque converter. Did a little work on it the other day as it wasn't moving just needed to fix the shifter and shift cable and add some trans fluid. Now the issue I'm having is the truck gets a transmission fault message and the speedo won't read my speed st low speeds and at higher speeds it's off by about 5-10 mph. Transmission came out of a donor truck and has matching codes and is the same trans. He replaced the torque converter aswell for whatever reason but I have verified it's seated and such. Everything is plugged in and no damaged wires. Fluid is fresh and filled to the proper level. What I'm wondering is is there anything I should check first? I have a snapon solus scanner I just forgot it at work so I'll be bringing it home tomorrow to Check values, codes and temps and hopefully go pickup some parts before the parts store closes. I have a feeling it could be the output speed sensor but I just wanted to get some tips from people that have more knowledge than me. I can provide any additional info if anyone has questions aswell. Thank yall for your time


Editing to add, truck shifts fine. No hard shifting. Speedo won't kick in until about 60mph and is a few mph off and the message shuts off. then when braking to lower speeds the speedo will freeze then drop and the message pops back up and overdrive light flashes, info screen shows no mileage or any numbers just dashes.

 

It definitely sounds like the output speed sensor could be the culprit, especially with the speedometer and transmission fault issues you're seeing. I'd start there since it's relatively easy to check. Also, when you get your scanner, make sure to check for any stored codes related to the transmission or speed sensor. You might also want to inspect the ABS sensors, as they can sometimes cause similar issues with the speedometer. Let me know what the scanner pulls up!

 

Yeah it ended up being the output speed sensor, i hooked my scanner up and there were no codes surprisingly but when i went into live data i had to reading from the output sensor so i talked to the guy i bought the truck from. His buddy read some codes and replaced the sensor because apparently it was bad originally. Come to find out he put it in at an angle so it wasnt making contact so i pulled it out, fed it in the right way plugged it in and problem solved! Now its got some other issues that seem like more of a headache that ill get to later lol