If you turn on both Motors at the exact same time, it WILL work 100% as long as both Axles are the same length.
Your problem is because the Gearbox between the 3 Axles will end up first taking power from ONE motor, it will try to EMIT power to the OTHER Motor instead of taking Power from it. The System behind it is really THAT crude, and outside of MC I am not gonna use this garbage ever again…
As for the Transformer Gearbox, I am not 100% sure if it is right or wrong, based on your text description of the Issue. Have you ever seen a Planetary Gearbox?
