I bought a 89 silverado from my grandpa for $500, he said i'd have to get it running right though. My problem is that it wont go into overdrive, the truck just sits idle and will rev up as if it were still in neutral. When I put it in drive the truck will run but has a hard time shifting. A mechanic friend of mine said it's probably a sensor problem( at least for the overdrive). I'm not sure if the shifting is the same problem. Anyone have any ideas or things I can try?