Cool, then you can buy the losi for $300 and then dump another $400 worth of lightweight parts, like bce or snr chassis, carbon towers, titanium pins and turnbuckles, aluminum hinge pin holders ect...also the diff outdrives have so much endplay out of the box you will rebuild those with new gears and pins with light weight outdrives ect... I'd say if you can't figure out a clutch problem then your doomed either way. I did all of these mods to my losi and the sc104x4 can out perform or keep up with cheaper electronics.

Your clutch parts need to be replaced or measure the thickness of everything and make sure the parts are correct. Also putting a larger 1415 in there won't help, since the 1415 has more tourqe than the 1410, that pinion is huge!

Scuff the flat on the motor shaft with sand paper a little bit then use blue loc tight on the pinion screw. Let it dry for a hour. Standard process.

The dogbone must be bending due to the way your shocks are setup, you might need to put a limiter or two on the shocks for the positions your running. Bend it back in a vise. Hope this helps.