i agree, and thats the 'business' end of the pump. the small slots are where you look in and see the brushes arc while running.

allthough with 2.4 it should not matter... especially with the ability to go to another RX when that one gives trouble. somthing (assuming it was a hold) got to the main recievers processor, where all the remotes feed to, or caused the same trouble with 4 recievers at once (!)