Hi all ..I have an older friend having an issue with his truck going in and out of overdrive back & forth..back& forth ..etc..any ideas??? Its an F 250 93 XL 7.3 L .thanks in advance. Rick.

 

Is this just driving around unloaded or when hauling a load? If there are no codes present(that is a hint.. check for codes) then it is probably just that your friend is driving right at that speed where the vehicle can't maintain speed in OD so it should be locked out.

 

the trans wont hunt (and you can't make it on purpose if you try) between 3rd and od with the idi diesel so long as the fipl/tps is set correctly.


if there are no codes from the trans,then suspect a worn tps.info:
https://www.ford-trucks.com/forums/1...ions-only.html

rick,also have your friend pay attention to the tach and speedo readings.if he sees any fluctuations in either of those,that would be the source of his trouble as well if it's not yet bad enough to toss a code.