[D13]

The trans guts are the same. The difference is the lock up clutch in the converter and the fluid path for it.

The converter clutch will not withstand heavy abuse, i.e. 400+ hp in 3rd gear with the clutch locked on. It is designed for 5-10% better fuel economy at highway speeds.

there shoul dbe an electrical circuit that shuts off the clutch at high throttle (or low vacuum).

As long as you aren't putting way too much power to it in 3rd gear it should be fine.