Quick update. I talked to one of the local transmission shops. Based on my description of the symptoms and the age of the vehicle he suggested I rebuild the transmission. He said whatever is wrong is internal and there isn't much he can determine without pulling the transmission from the vehicle and tearing it down. Ballpark he said $2000 labor plus parts. He couldn't guess at how much parts would be as he said it would depend on what needs to be replaced which he won't know until it's torn apart and can be inspected and tested out of the vehicle.

I'm not convinced my problems are severe enough to warrant this yet. He warned that if I 'melt' the transmission, the cost to repair will go up significantly. So, I need to factor that in.

Still collecting more info, so opinions and suggestions are welcome!