Back in the day radio shack made the Extreme Machine and it was the first of the giant 4WD trucks with dual 540 motors and later came the identical Nikko Hercules. They had tons of power once they got rolling but when you would try to climb a big hill or cross a mud bog the power just wasn't there. I remember trying soo many obstacles off-road that it had plenty of potential to conquer but just not enough power. Running a 7.2v 1500mah battery gave it about 5 minutes of run time which was horrible. Enough of that bull *censored*.....
Using RC4WD's 4:1 gear reductions on the truck I must say, its a whole new truck. I had to modify the housing to get them to work but it was no big deal. This alone makes a major difference on run time. I also cut the front bumper for more clearance and mounted the 8.4v 5000mah battery up front for better weight transfer. The rear differential is locked as well.
Improvements:
More than 5x the torque
1 hour+ run time when doing nothing but climbing
Much steeper hill climb abilities
Will go through almost anything off-road
This truck now deserves the title of the Extreme Machine soo much infact that it can even blaze through 2-foot tall grass without even slowing down with both diffs open where a 2.2 Axial SCX10 kept getting stuck.
I posted a short hill climb video at the bottom