We have experienced the occasional breakage here, sometimes on initial assembly. We think the hole may be slightly undersized, and will address this in the next production run.
Amazingly, it seems not to matter, and those with the problem successfully run their cars for long periods crack and all. See the forum at
www.2wdrc.com
If your car is broken beyond use, see the dealer who sold it and, assuming he has a #1001 chassis in stock, he should replace it. We will in turn replace the part for him at no charge.
If your car seems tight and will run, please run it; the threaded insert does most of the work and you should be fine. As I said above, about 10% of the chassies have this problem and we have yet to see one that does not perform well anyway. Probably over-engineered...