Anybody know what causes this or how to prevent it?

[Kur]

Took my mt410 out bashing today and would hear a random grinding noise. Every time I checked I found rocks in the chassis and figured they were grinding on my spur gear. Cleared the rocks and the noise went away for a while.

But when I got home I noticed the rear drive cup rubbing on the receiver box and the bearing popped about 1/3 of the way out of the rear diff housing.

Any ideas?

 

[Kur]

Figured it out as soon as I got the rear end off. The set screw on the drive cup came loose. No signs of loc-tite at all which is weird because I could swear I put it on when I assembled the kit.

Checked the front diff to be safe and sure enough the same thing was happening there too.

 

[Matthew_Armeni]

When putting thread lock on metal parts it's always a good idea to use motor spray or something similar to get off any remaining oils from the machining process.