I was able to strip down the turbine as was discribed. The brgs look in excellent condition. I strongly believe that the problem is with the preloading. However, I ran across a bigger issue. Upon removing the turbine from the housing, I noticed a piece of the CC & lots of small burnt pieces. It tuned out that the inner part of CC was deteriorating - that would explain the few "sparks" I saw. I was told that the turbine had INCONEL CC, so I don't know what happened. So I will be sending it back to Gabe at JetJoeUS for repair. I hope it will be covered under warranty. The funny thing was it was running great the whole time. Idle at ~40k @ 498-500 deg & FT at ~160k @ 618-625 deg. It had a total of 18 cycles & 165 min.