Well my truck has a NV4500 and a SB Dual Disk 3850. It will not go in gear, so I would think it has a bad slave cylinder? Well I bought the SB heavy duty system, installed it and still it won't go in gear. The system was supposed to be pre-bled and ready to go, but i still tried to get air out before a installed it. In the end though, the truck will not go into gear will it's running. If I put it in gear, then start it, the truck will roll forward as it cranks and once it gets started the clutch will not disengage, the truck just keeps going forward. So what else could be wrong here? I took the trans off today so I can get somebody to take the clutch apart for me. Could a throwout bearing or fork be bad? I need some help.