Got this truck from starscream today as a roller and finsihed putting it together a little while ago. Ran a pack thru it and everything seems to be ok. I am running a Plett Maxximum on a maxamps 4200 3s pack (3s2p 2100 cells). The Mamba max seems to be doing ok, after 30mins of mixed bashing everything was barely warm. Truck is geared 13/46, so about 35mph with stock tires. I may gear it up to 40 or so, but I wanted to test my home made hardened pinion.
What I did was took the 1st 13t gear pinion of an emaxx input shaft. This gear appears to be factory hardened as it was very hard to drill. I took the torch to it and heated it up till it was uniform red and let it cool. That softened it up enough to drill and tap easily for the set screw. I used a m4 thread screw with a 2mm hex, std size for larger pinions. After I drilled and tapped it, I heated it up to red again and then quenched it in 10w30 oil. After the run it had barely worn the black off the gear so I guess it is ok. I will run it for a while and see how long it lasts. The mesh is very smooth, so the gear must have the correct pressure angle to it. It is also reasonably quite too.
I am very happy with the performance and would recommend this combo to anyone, much better than a feigao l can and the same esc and batts.
Heres the pics, with the pinion fresh out of the oil.