I couldn't remember the right model trans,that's why I said the 727 version :). He used to rebuild transmissions before the electronic stuff came out and it has him puzzled.
If he used to do transmissions he should be able to do a 46re. Their kinda old school electronic if you will. The main guts are basically 727 with a OD unit added on.
You might try taking it to Autozone like Tony mentioned to see if they'll read the codes for him. Easier than doing it that way.