Dave, I am currently replacing the same type of transmission in an International dump. 90% plus of our fleet has Allison trans. They work great. This was a problem with fluid loss and wipe a clutch. Of the electrical issues we have, I see the wiring to the TCM rub on by the drive line. The TCM is mounted above the output yoke is really close.

As with the push pads. Just off hand it sounds like the push pad may not be working right. Some displays have a 2 number display. Typically top gear IE 5 and the gear it is currently in. Others have a single display, with the max gear displaced or D. I want to say we have replaced 2 touch pads in my time here

Your statement is correct once you push R or D The transmission will go into gear. Pushing the down arrows is the same and pulling the shifter into a lower gear. The pad tell the TCM what to do and the TCM tells the pad what it did. I would be looking for a wire or connector problem. Hope this give you a little light. If Allison DOC was working, it would make short work of this.

Jason R. Gohn
Technician/Shop Foreman
Greene County Highway Department
Springfield, Missouri, USA