whenever the diff turns not so smooth anymore, as fresh built.
it is then time to do a re-build.

sorry about that double question.:002:

Do you guys do any daily maintenance of any elecrtic cars you have aside from cleaning the tires lol?

no problem.
did my explaination help you?
daily maintenence: keep it clean:p

The only maintenance I do is make sure all the bearings are turning right in the tranny, diffs, etc. Every once in a while, I remove the motor and spin the shaft by hand to feel how smooth it is. If it turns rough, I clean or replace the bearings. The motor bearings spin the fastest/most and as a result, would exhibit the most wear if they were not clean.

how rough is to rough if you spin the motor chaft by hand?
how many bearing usually does a brushless have?

Well, a motor should turn easily. This does not include the resistance from the magnetic fields, which fells "bumpy". Dirty bearings will feel like it's dragging and might even make a gritty sound.

There are bearings at just the front and rear of the axle, so two. I'm not sure, but a higher-end motor may have two bearings on each end.

what kind of oil should i use to clean these bearings?
and will it be ok for use on all bearings?

Thanks.

I don't know if it's right, but I use an air compressor to clean them and then use some WD-40 for lube. Seems to work ok.

i use brake parts cleaner and lube with syntetic engine oil, 0w40.