@Cgray Any update from your efforts here? I recently scooped up an A1 and am running into the same issue, particularly when getting going from a stop once the truck has started to warm up. I've started troubleshooting to eliminate the low-hanging fruit of trans fluid level, fluid state, filter state, and am going to start pinning some wires this weekend to check electronic components and easily accessible wires.
I'll also echo the possibility of a 'wet' keypad as previously suggested by NDT and Suprman, the truck has the original clearance lights and gaskets which I need to replace, and had allowed some pretty noteworthy water intrusion into the cabin during heavy rains.