2fat

i have a traxxas slash and i just put a novac gtb 7.5 in it and it runs very hot what gearing should i run in it.

Amoeba

iTrader: (2)

How hot is hot? What spur/pinion is it?

The GTB w/Novak 7.5 motor final drive ratio is about 11:1 as recommended by Novak. Assuming you have the stock 86t spur, go with a 21t pinion for a FDR of 11.14. If it's still too hot drop a few teeth on the pinion or go up a few on the spur.

2fat

running stockgear and pinion. so hot that it shuts off

GLwagon

iTrader: (22)

Gearing is dependent on driving style & track size...
If you're just playing then it will take some guessing.

I personally have ran as low as 90 spur & 13 pinion on a 7.5
That was a small carpet track.

It is a lot safer for the stator & rotor if you start lower on the pinion & go up...

Amoeba

iTrader: (2)

So you're not temping it? It could be the motor or ESC overheating which are two different issues but the GTB doesn't appear to have thermal protection built-in. What batteries you running? If NiMH batteries you need to make sure the LiPo cutoff isn't enabled. Which 7.5 motor is it? Are you certain you're not using Profile 6 on the GTB (brushed mode only)?

Obviously dropping teeth on the pinion will help reduce motor temps but without knowing if it's the motor or the ESC that is getting too hot it's hard to help. Each issue has different ways to resolve them.