Yet I still have no overdrive

Hi Fancybutter,

The way this overdrive works is the servo that you replaced is responsible for apply a band inside the transmission that holds the overdrive drum which achieves the overdrive gear ratio. If the servo is okay (assuming since you replaced it) then the issue is the band itself inside the unit is slipping and not holding any longer. This is not uncommon as the band material gets hard and no longer has the gripping ability like it needs. I attached a diagram on where this band is and the application chart that shows the Overdrive band is the only thing applied that is not applied at other times. The fact that you said overdrive is the only issue shows that the other components are okay.

Let me know if you are going to rebuild this unit yourself and I can send you the procedure if you want. It will be quite a few pages so I will only send it if you are going to do it yourself. Thanks.

Sorry. I missed that one but I don't think it is related to the overdrive issue.

Here is the test for it not working at all. Let me know what you find with this but due to the fact that you already replaced the speed sensor, and assuming your brake lights work, and horn works, then it may just be out of adjustment.

I attached the test and the adjustment procedure. The adjustment procedure is pretty lite so I looked for more information and couldn't find it. If you need more, let me know and I will try to dig deeper. Thanks