C34 Transfer Case Clutch Packs

[CaSilvia]

I have been having an issues lately while driving in the snow. Once the car detects slip and starts sending power to the front I get a massive vibration throughout the car. Once you let off the throttle or the car shifts gears it goes away. Anything over half throttle it is guaranteed to vibrate.

Attessa and T-case have been flushed 2 times in the last 2 months due to leaks. Leaks have now stopped. No air in the attessa lines.

I am leaning towards the clutch packs not fully engaging, car has roughly 85,000km on it, stock motor.

What have others done when the clutch packs start to go, replace the standard units or swap in the GTR T-case which the larger clutch packs?