Unfortunately, the Helion (Hobby Town Brand) is still relatively new compared to big names like Traxxas, Losi ETC. So getting parts to your local hobbyshop has been a logistical nightmare and thats just for stock parts. Being that they are still so new a lot of the aftermarket companies have yet to develope upgrades. However I have had customers with similar issues. I found that their gear mesh was to blame. Utilizing a piece of paper I would pinch it between the spur and pinion gears. This gives me the perfect spacing between the two. Not too tight and not loose enough. Customers that I have done this set up for have yet to come back for another spur gear, instead its other parts from them crashing into things. Another thing to think about is your slipper setting. If it's too tight, you increase the risk of putting too much stress on the gear and again stripping it out. Start it out lite and make small increases per your drivingstyle and driving environment.
Hope this helps and happy playing