Nissan X-Terra Naftero

I have a Nissan X-Trail Naftero, by accelerating the engine at approximately 3600 rpm in any change in the speed box produces an almost unusual buzz inside the vehicle, outside this RPM regime, it does not produce any noise, apparently this RPM regime, makes any component that produces the hum. Also when the vehicle is detained and accelerate the engine at 3600 rpm it produces something similar and an important vibration is observed in the transmission tree, although it is not rotating. What I did was to place a cardboard tube inside the cardan tree tube, decreased but was not completely eliminated. Someone has told me that it can be the catalyst. If anyone has had a similar situation, I would appreciate your help.