motor and batteries stay cool, esc gets hot

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I just got a warrior 9920 and a Nemesis 6xl and am running 4s lipos in my Emaxx, and finally have cool motor and batteries but the esc is getting real hot after about 2 minutes. Since the motor and batteries are cool I don't think it's drawing too much current, what could be the problem? I have brakes turned down to 35% to keep load off esc. I'm running all UE parts and 40 series mulchers with 14/51 gearing. This motor is a torque monster so is supposed to handle bigger gears, but would gearing down help? I origionally tried a 16/51 but after 14/51 the motor was warmer...was told not to use a fan as that just puts thermal meltdown off longer as it masks the problem?
Thanks for any insight!

Also use Gmaxx 2nd gear conversion...

Would using ubec help it run much cooler? Do I have to cut the shrink away to get to the jumper?