I have a 00 1500 with the nv3500 manual trans. Literally overnight reverse just kinda, left. Every other gear works fine, still drive it to this day. The trans shops are telling me it'll be $500 to pull it, tear it down, and diagnose it. Then parts on top of that price. I throw the bs flag on that because if your job is transmissions, you have a good damn idea of what's going on. So on top of it going out overnight, I can be doing 70 down the highway and put it in reverse, don't ask why I tried it but I did, so there's something that should prevent that. Basicly it just acts like anything involving reverse was abducted by aliens. Any thoughts on what's wrong with it?