My guess is the lube on the one-way bearings.
Non one-way lube causes the roller bearings to slip against the retainers. So your one-way unit does not give you any drive to the front wheels.
This would have the effect of making your car RWD. Would also explain why your car is squirelly under power.
Degrease the oneway bearings and re-lube with a one-way oil. Machinery oil etc.
Should do the trick. (I hear non-rc oil is good. Nothing too slippery. Sewing machinery oil is often quoted. Cheaper too!)
Especially seeing as nothing else has changed on your car.