check your belts and diffs, take the motor off and push the car.... if it noises, disconnect front belt, if it still noises, take out front dogbones....this way you can isolate the origin. It happened to me once, but was motor bearings... (i have a brushless).
The Blue Armada: Tamiya TRF415MSXX, Tamiya TA05MS, Tamiya/Xenon TA05
Novak Brushless, Orion/Peak LiPo batteries, 5-cell
Sanwa M11 DSSS, KO Propo Servos