Im in the middle of figuring out some other things with the truck right now, but the matter at hand is the overdrive wont work. when i depress the button the O/D Disengaged light come on and goes off respectively. but does nothing mechanically. Can anyone point me in the right direction?

 

broken snap ring or bad overdrive unit.... possible a loose connector at the transmission? get it on a code reader...there will be codes even though theres no light...

 

To verify a mechanical or hydraulic issue, you can attach a pressure gauge to the 1/8 npt pressure port just in front of the extension housing on the left side of case...If there is ANY measurable pressure when the trans should shift to fourth, it is indeed mechanical or hydraulic( time to remove and repair)..

Brian

 

Ok thank you for those posts. Ill take a look at those today.

 

What year is the damn thing? lol Please add all the info about your truck to your sig and profile. You can try the key trick to see if any codes come up.