Bad Connection?
I have an '04 E350 with the 5.4 and 4R100 trans. I've been having issues with the trans that I'm almost certain are wiring related, but wanted to confirm with the experts.
Speedo sometimes bounces during normal driving, usually during acceleration but no codes or flashing o/d light
When starting from a dead stop up an incline the speedo quits altogether, trans goes into what feels like neutral, o/d light flashes. Turning the o/d off via the button brings the speedo back immediately and van drives forward without issue. This has happened a few times and last time set a code of P0720.
Possibly unrelated, but "Brake" sometimes comes on, usually when the trans issues are happening. Manual says this is indicating low fluid but it's not low. I know the VSS can cause some of my issues and also cause the ABS light to flash, but this isn't the ABS light.
I think I have a wiring issue simply because of what happens when it's on an incline. Maybe the tilt causes the harness to swing and make contact with a chafed wire? What do you guys think? How would you even troubleshoot this?



