When to check or change diff fluid?
 

I have a Losi 8 1.0 with a v-spec. It is new. I have approx. 1.5 gallons ran through it. Mostly breakin. I have done a couple practice days at the track and am going to be competing in the local club series. For my own knowledge regarding break in, how often should I be changing the fluid. Is it good for 2-3 gallons? Thanks for your input.

RE: When to check or change diff fluid?
 

There's no rule for how often it should be changed. I found that if the car is setup with fluids that are too thin the oil can 'cook' and go bad fast due to heat when the diffs 'diff out'. In that case you need to change often.
I generally change fluids once/gallon if not more often.