I bought an associated TC3 from my friend months ago and noticed that the differential behaves like an open gear differential. When one wheel slips it keeps on spinning and doesn't transfer power to the other wheel. Is there a way to prevent this?

There are a couple of ways to stop this from happening. One is to tighten the differential and the other is to adjust your car's suspension.

If it is difficult to rotate one tire while holding the center drive shaft and other tire stationary, I would not recommend tightening the diff (as it is set properly). Proper diff adjustment is critical for good performance.

You need to setup your car so that you do not unload (or lift) a tire while turning (I assume that's when it's happening). Adding a sway bar (or going to a stiffer one) can help. Going to a stiffer spring and / or heavier shock oil can also help.

My best advice is to talk to someone at your local hobby shop about how your car is handling and where you are running your car.

Good luck,

i8tweety