Hi, let me rephrase your question. Are you referring to, why is there some free play when you hold on to one wheel and the other one could spin back and forth about 15 to 30 degree, with the motor and pinion attach?
Ok. There should be some free play. This is just some manufacturing allowances to ensure the drive train is free to rotate. Due to the fact that baja king could be using gear differential, there will be more free play. Adding that to free play in all joint cup, you end up with alot of free play. But it normal.
To minimize it, Ball differential and CVD ( Constant Velocity Drive ) can be deploy at a cost. That will be something to learn all together again.