If you're in 3rd gear, with the Torque Converter locked, the ISS should match the OSS. If not, something's "slipping". So, monitor the "Comm Gear" PID, ISS and OSS to check this. In 4th, the OSS would be higher than ISS with the TC locked and in lower gears, the OSS will be lower than ISS.
Again though, the TC has to be locked, because if it's not, they will always be different.
I'm puzzled when you say it won't shift to high gear (4th) when cruising. Do you mean if you are holding a steady speed at say 60 mph on a level highway the truck never gets into 4th gear? If that's the case, something is badly wrong.
- Jack
|