Didn't expect this to happen, especially so soon

I was driving it at home when I was hearing a clicking noise. Not sure where it was coming from I started trying all sorts of different things, but whatever I did, I could not figure out where the noise was coming from. Lifting the car and placing it upside down did not make the noise. It was something that was happening while under stress. But then, I'm driving on a smooth floor and different speeds, what possible stress could I be putting on it? The only thing I can say is that the noise happened when I had full steering on either side. I lowered the travel to 60% on each side so as not to oversteer. Still made the noise. I suspected it came from the rear axle, so after lunch (important to work on a full stomach ) I removed the rear axle and decided it was time I see what's inside. After all, I only drive this truck 3 or 4 times and have never had reason to do any maintenance on it. It was always a slow easy drive, no stress or anything like that. My YouTube videos show exactly how I drive this truck, So I took it apart, removed the grease that came with it although everything still looked brand new, and put some marine grease I use on all my other cars. After I finished assembling the axle, I started mounting the leaf springs and BANG, this happened  

Wrote to Boomracing.. We'll see what they have to say. Do they even sell that part on its own??