It is almost required by law to add this disclaimer to any motor sharing thread:
When building ratchets and differentials it is very easy to introduce extra friction losses with every additional axle or 4-bar frame that could twist out of the alignment.
I’ve seen some really well built robots doing motor sharing, but it took months to get it right.
On the other hand, I’ve seen some ratchets and differentials that were painful to look at and think how much extra friction they introduced. The teams would have been much better off just doing non motor sharing designs and spending extra time on practice.
I don’t want to discourage anyone from doing motor sharing. My team is doing that third year in a row. I just want to add a word of caution that it takes considerably more extra time to get it right. Please, see these topics for more info: Passive transmission, Differential Extra Motor, Differential transmission - power takeoff from the drivetrain motors