how strong is the 3.3 tranny?

[BrianG]

The tranny is ok. It held up to a 9XL on 14 cells forever once I addressed all the weak spots. Noteably the pins that hold the gears to the shaft. There is a sticky by yours truly that explains what pins to use.

Just be aware than if you keep the 2 speed tranny, you'll also need to keep the mechanical brakes (which I assume you are since you'll be designing it to swap back to nitro).