On my 96 7.3l, i had issues with my overdrive. Whenever you would turn the lights on it would kick out of over drive, and unless you were accelerating it would stay out of overdrive. Brought it to the shop, they found out that the factory installed 7-prong trailer plug was shorting out on the frame causing the issue. got a new plug and harness from Ford ($200) and now it shifts perfect again (even after 700,000 and no serious issues)!

Man I love these trucks!!! They don't die!!!

 

Does the sped-o indicate "7" in the 700,000? Can you take a picture and post it? Reason to ask is we know from 399,999 miles it rolls over to 300,000 miles because there is no segment portion to display the "4" properly.

Inquiring minds want to know ...

 

now im curious what do you mean by does the speedo indicate 7? is there a possible way to read the odometer past 399,999?