Useless Information 

Upgraded the battery on my kids Power Wheels to a drill battery and low and behold the gears inside tear apart. Hope this helps anyone who needs it. 

I didn't bother to create the large gear model because I highly doubt it's going to break for anyone, including myself.

Semi Important Information 

The gear box was from a UTV MX kids ride-on. 

There are a couple different models of gear box's online that look similar. Mine had WW1 printed on the outside cover. A couple forum posts confirms that its the 550 gearbox but I cannot be certain. Let me know in the comments. 

Important Information 

Use Poly-carbonate or Nylon, preferably with carbon fiber. 100% in-fill. 

Tolerances are tight, so shrinking becomes a problem when placing the gear over the shaft. Calibrate your machine to your filiment. 

Comment below if you want any modifications.