Just had a old e maxx given to me today ! Has a evx 14.4 novak serviced buy traxxas not the evx 2 that's under the legacy model's on traxxas site .So will the two speed tran's handle a brushless system ? By the way it's in good shape.

No, the nylon idlers will not last under even mild BL. Upgrade to either the UE idlers or the set RC Monster sells (hardened, lightened steel). Then there is a flimsy, thin roll pin on the input shaft (top shaft) that secures the gear at the end. This is a fairly easy fix - remove old pin and fashion replacement from a allen L wrench or the shank of a drill bif of the right size. The allen wrench was easiest - takes a little filing on the points to get it to fit and still be tight.

Eventually the gears will go, not sure which, but they are not made to handle BL power. You can minimize probs by locking it in 2nd (just leave it) or doing gorillamaxx 1 speed conversion which just leaves 2nd gear in trans and discards the rest.

My 3906 is locked in 2nd and has the UE idlers and has been OK with an 8XL that I have esc turned all the way down for. Low power setting was enough I still killed the diffs and twisted the stock axles. I upgraded to 3.3 knuckles, bulks, turnbuckles and wheel drive axles. I used UE TI center drives. I replaced the diffs with stock 16.8 diffs. Been solid since getting all that done.

Thanks for you in put I just but to 7 cell 5000 nimh in it seems good for now.

Could you tell me what a safe temp is for motor's would be ?

I try to keep mine below 160F but that depends a little on how hot it is outside too.