Hello Sandside
You need to check your drive voltage. 99.999% of problems involving clicking come from drive voltage errors - assumptions are easy but power supplies do not always deliver what it says on the tin... I had two modellers recently who swore bling their power supply was 12v, but on measuring the result was in one 17v, (unregulated 12v supply) and the other 21.5 volts (faulty wall plug supply. Train-set controllers are the worst culprits though - the terminals marked 12v uncontrolled are always 16v or more...
Clicking is generally caused by too much power - the drive train is far more powerful than that in T and therefore if you over supply power, then you force teeth past each other.
If the cause is the 0001% it'll be a damaged tooth - probably caused by initial-over voltage but still possibly a moulding fault - in that case, like all customer issues, we would repair or replace it for you without question as we always do.
There are many details in which Cobalt leads T, but I am not responding for a product discussion, just to clarify your problems cause.
Richard