Replacing my SRAM SX rear derailleur and NX cassette

Over the past month, warranty repairs are finally done. 

Top - replacement SX 12 gear derailleur

Bottom - Non working spring back derailleur 

So my issues all started when I was riding with some friends. About six miles into our mountain bike ride, as I was pedaling, my chain dropped.  I stopped to put is back on the front chain ring but noticed the one jockey wheel on my derailleur came off.  I was able to find the parts along the trail I was on and thankfully repair the part that came off. 

When I got home, I looked over the derailleur really good and made some adjustments on it.  However, this time the chain would climb up the cassette but not return back down.  After working with it for some time, I was able to start of the process of getting a new replacement one under warranty.  The process was pretty fast, but not fast enough, as I had to do my July 4th, 20 mile trail challenge with limited gears with the new derailleur arriving the weekend after. An update I am loving about the replacement derailleur is the limit adjustment screws are now allen key screws, replacing the Phillips head limit screws. 

older SX 12 gear derailleur with Phillips head limit screws

NEWER SX 12 gear derailleur with allen key head limit screws

After getting the new derailleur attached and adjusted and working great, my chain, which is under two months old, was skipping around and having a hard time on the third to biggest cassette cog.  One tooth was missing on that particular cog.  Knowing that this part too was under warranty, I started the process to get it replaced also.  In the meantime needing to keep riding and training, I just had to be aware of when switching gears not to ride in that cog. Over the two weeks while I waited for the replacement part, the cog went from a first grader missing one tooth to a hockey player, now missing a section of the cog which I think should have been three or four teeth! 

New cassette arrived and I was able to place it on the wheel.  All is good for now as I have some challenges and training goals I am looking forward to. 

"Look Ma, I have all my teeth."

In the end, I understand the groupset, I am running is not the highest quality SRAM makes and I am looking at saving up some money to upgrade before too long.  SRAM and the local bike store I have been dealing with have been great.