Another issue on the 97, 6.5 is I lost overdrive . At first it would engage after a few miles and they it would drop back to third gear after a few more , sometimes shifting back to OD , but now it won't go into OD at all. It shifts great up and down 1st to 3rd and back to first, no slipping at all but OD will not engage at all, even by moving the shift lever fron 3 to OD it just stays in 3rd..

Is there some controller outside the transmission that gives a signal to shift up into OD other than the geat shift ? Is there a way to add a manual switch to engage OD when needed . I heard rumours of this but can not find any information.
.Opening the transmission at this time is not an option. 2700 RPM on the highway is a fuel consumption disaster.
Thanks Pete

 

Can someone post a wiring diagram for the transmission controls for this 97 , 6.5 automatic 4x4 ? or a link to one ?
After hours on line I am striking out finding the wiring diagrams that show the tranny wiring, and controls.