What is code for? Trouble shooting for a customer. Starts up and immediately goes in reverse. Put in forward and goes to neutral. So transmission stays in reverse when lever is in neutral and in reverse. Does not move forward. Customer said that originally truck would quit shifting to forward after running a bit, that's why they changed shifter. After they did that it did the same thing and but started making a grinding noise and quit shifting to forward. I'm thinking transmission is mechanically stuck in reverse but when you try and shift to forward it causing it to engage both clutch packs? Any ideas?