9xl and heat

[slow-stampede]

I got a revo with an emaxx tranny on it geared 14/64 and stuck in 2nd. It's got the stock diffs and 40 series tires. I'm running a 9xl with 18 cells and after about 6mins of running, the motor is too hot to touch for more than a second. The 9920 and batteries are barely warm at all. Do these motors run this hot without a heatsink, or is my gearing all wrong.