While coming back from the Shied Diesel Ex my allison decided not to go into overdrive after I accelerated hard. When I got home and checked the codes they all had to do with the accelerator position or voltage issues with the accelerator (1125,2122,2123,2128,2133) This is the first time for anything like this. what's happening- is this an engine problem or a transmisson issue? The truck is a 05 with a hypertech III, K&N filter/intake, MBRP 4" turbo back exhaust. The Allison has a ATS copilot with no other mods.

Bob

My first guess might be a problem with the APP sensor. I'd probably clear the codes and see if they return and if averything works right; If they don't return and everything is fine, it could have been a fluke. If they do, then it could be a loose connector, bad APPS or something else...