I have had a Caldera 10E for a few months now and I drive it hard. Haven't had any of these issues with it so far so sounds like maybe you just got a bad transmitter and maybe a few loose screws on it.

I appreciate the maintenance tips about greasing the differential and threadlocking the wheelnuts. I'll look into that too.

I put larger tires with heavier tread on mine and although it looks cool and handles rough terrain better, it has slowed down the top speed somewhat.