***** and moan all you want but it wont solve problems. Break-in is the hardest part on any r/c truck. Simple fact: a tight differential setting WILL NOT cause the spur gear to strip out under half throttle. Check the gear mesh and making sure all the screws are in on the the chassis will GREATLY reduce the chassis flex. And 3 tanks of fuel isn't enough to break-in a differential. When I rebuilt mine with the carbide balls it took me around 8 or 10 tanks of fuel doing figure 8's in a parking lot to even begin to get the differential to grab and not slip before the slipper clutch. New duratrax diffs will slip.
I race my duratrash evader and it does alright. Weakest link right now are the steering buckles and tie rod ends (that's right, it isn't the diff...and I STILL HAVE PLASTIC GEARS). I've managed to strip 1 (one) spur gear but only through my own stupidity (left out 2 forward tranny screws on chassis).