Hey guy's thanks in advance for your help.
I am having new/old issues with my 1/16 thunder fire. (also my friends thunder fire)some are my problems and some are his.
Drive gear (86032) strips easy.
Universal joint cup broke on front transmission (86020) too much angle?
Air bubbles in fuel line during running engine stops/after that hard to start/then way too hard to start.
Mine is starting to do this.
Also pull start not grabing.
He is running Traxass fuel.
Binding when trying to free wheel?

Thanks again for your help
DCN10

make sure your gear mesh is set corect. the cup i dont know about. the bubbles could be from a cracked line or a bad seal on the fuel tank lid. the glow plug could be bad also. the pull start is not grabbing because the oil from the traxxas fuel has so much oil in it that it gets into the one way bearing so then it slips and doesnt catch. the binding is most likely because your brakes are improperly set up. try loosening them up a little bit.