did eney one bother to read the whole so called facts of the crash . in the first bit the speed was 155 in the 2nd it was 85 and the driver was on the phone ... and it all comes from.... the urban legends site . ..
try here http://www.nitrotek.co.uk/spare-parts/spare-parts-for-nitro-radio-controlled-cars-buggies-trucks/spare-parts-for-1-8th-nitro-cars-buggies-and-trucks/vrx2-buggy.html
been using this grease for years in fg diffs with on problums... if you wont a thicker grease try this http://www.modelsport.co.uk/ansmann-racing-high-speed-differential-grease-90g-/rc-car-products/34326
if the battery is to flat to run a manual speed controller i would not think it would be a runaway more of a slow crawl away .. if its like the the hornet i had you will see it slow down before you lose servo,s
it looks to me to be your servo saver or lack of off one. the round servo arm dose not give enough travel ... ......................................... beaten to it