I've seen Volt transmission
I've seen Volt transmission and it's the same as Toyota's hybrid vehicles.
Also in Toyota, engine engages with the wheel only at highway speeds. At low speeds it would only recharge the battery if necessary. This should be the same for the Volt as it uses the same design transmission. So basically Chevy could have transferred Volted system to comparable size SUV like Equinox.
I think the main reason to abandon this program is they couldn't compete with toyota's prices.