RE: When breaking in gears.......
i take it these are Heng Long boxes you are running it with 'tooth paste/grinding paste' ?
i fitted a set of impact boxes and asked this question to the supplier about running in the boxes with paste type materials, he passed me straight onto a guy at Impact. He asked me if i was mad!!! tooth paste, he said it was like putting sand in a car gearbox, something you should never do. He told me to use any sort of lube, i suggested motorcycle chain spray (it sticks like sticky goo and doesn't fling off like normal grease does) he said that would be ideal. All i had to do was connect them up to battery and run them for 30 mins, then fit them to the tank. He also said the boxes would quiet down after a while, which i would agree with.
Kev