Castle Sidewinder help

[5150 Krawlers]

Alright so I just bought my little brother a brushless kit for his rustler, its a castle sidewinder/5700 motor combo, We only ran 4-5 intellect 3600mah nimh packs through it........one at a time and monitored temps very closely.

So what happened was we went out one morning with a fresh 6 cell 3600 pack, and within 4-5 minutes the ESC let the magic smoke out, I could hold my finger on the motor for about 5 seconds before it got warm. But the ESC was pretty dang hot.

I tried turning it on later and it made a horrible castle tune and would only shake in forward/reverse.

Did I do something wrong? Dont get me wrong I am hard on stuff but have honestly babied this setup with him since we got it......what gives?