My friend has a 91 Dodge Cummins that wont go into overdrive. The place where the speedometer cable plugs in is stripped. The dealer told him he needed a pinion adapter but they dont have one and cant get one. I have searched the forums for a answer and it seems like he needs a speed sensor (TCM) I think, But nobody gives any part numbers for anything. Can somebody give me some part numbers and maybe some diagrams, or pictures?

 

Before looking into that, do you have an overdrive off switch? Check into what's going on there. I don't know if a malfunctioning switch is the problem, but it's cheap to fix as compared to the other option.

 

No there is not an off switch. The female portion the Speedo cable goes into is stripped because when we wrap a piece of paper around it (the cable) and jam it in there, overdrive will kick in, But this is no permanant fix. Sometimes when going down the freeway it will just kick out of overdrive and then your stuck going 45 on the Intersate.