The only thing electronically controlled on the 32RH is the torque converter lock up. Everything else is purely hydraulic. It sounds like the centrifugal governor is sticking and not allowing enough line pressure for the trans to shift. A very seasoned transmission guy told me that when that would happen on the torqueflites, he would take it for a drive and stay at 40 mph. Once he was there, he would throw it into park. What happens is the parking pawl is trying to engage onto the teeth but can't at that speed, and the ratcheting that it creates vibrates the governor and causes it to unstick. If you feel like changing the governor, it's not too hard to do. It's located on the tail shaft on the back of the trans.