tc02c evo idler gears

[big red bus]

Have just started to use my t c02c evo. I brought it brand new but guy had already built it. Now i finished it off and got it working. Used for first time last week and within 4 laps of the track at very light speed, when landing from a jump one of the idler gears stripped . Ok so i stripped down cleaned out debris and replaced gear. Tun tonight and same thing as happened . Soft landing and atripped. Any one had similar problems or can point in direction of may have been put together wrong or may be the problem. Any help much appeciated. Thanks