If the car is fully warmed up and I'm for instance on the freeway and need to speed up for any reason it will go to shift down a gear . While in that process it pulls out of the gear it's in and goes into a neutral making the engine rpms spike and then slams into gear. I have my fluids changed according to the book. Every fluid in this car doesn't stay clean for longer than it takes to pull out of the dealership parking lot. It turns black instantly. Possibly why it's having tranny slippage?