Based on my experience ... BJ74 .... Auto gearbox .... Here are my observations:
If you accelerate at a normal rate (Not NASCAR restart rate) the transmission has a tendency to shift into overdrive too quickly which can be a real pain, especially on an incline. One option is to shift manually, perhaps staying in 3rd for a longer period especially on an incline. Like with most automatic transmissions, if you press the accelerator far enough the logic takes over (think passing gear) and off you go. (It actually has fairly impressive acceleration in this situation)
This parts important ..... Virtually all Toyota diesels are slow regardless of transmission. If you want to go fast, buy a 2500 Diesel Dodge or Chevy and forget the little Toyota.
Disclaimer ..... I'm on my second Toyota automatic transmission and wouldn't hesitate to buy another one.
Hope that helps ......