I converted a Bruder dozer and being using this model for over two years now and still going:
https://www.dx.com/p/zndiy-bry-37mm-...l#.XtvqlOd7lEY
Cheap and probably not the highest quality, but just what I needed to do the job. Lots of power and easy rev up.
Like someone said above, the worm gear thing doesn't seem to sit well with a lot of "Stop and Start" kind of things.
For ESC I'm using something similar to this:
https://hobbyking.com/en_us/hobbywin...en_us_products
And for battery one of these:
https://hobbyking.com/en_us/zippy-co...en_us_products
Is less voltage than the ESC calls for, but the motor run nicely on them. For a dozer, you really are not looking for speed (at least in my case) and the 30C rate "LiFe" battery is just perfect. It keeps the dozer going for well over 45 minutes without missing a beat or motor overheating that I could tell.
Heck, I had to use about 3 pounds of scrap metal to make the dozer heavier cause the tracks were spinning a first sign of resistance from the blade.
Any way, that was my rant for the day!