This is a common failure to the Ultra engines if somehow the drive line or pump has been messed up especially when the engine has been heavily modified. We got an official answer from The Green Team in USA that states: It's difficult to say for sure, but if it had a turbo, they may have put a different pump or impeller in it. If they did not have the correct driveshaft spacer (in the impeller) the driveshaft may have pushed forward on the rear of the engine (crankshaft) which could wear out the thrust bearing. Also, if they were using a stock pump with a turbo, they may have had a pump bearing fail which will allow the impeller to move forward and push on the back of the crankshaft and cause the thrust bearing to fail.
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