When I start driving uphill I press the accelerator and it feels like the car is in neutral (not moving and even rolls back). As I press the pedal more it very slowly starts to move. This only happens for the first few minutes of driving (after 1st start when she's relatively cold). It doesn't happen at all after that. My assumption is that it's transmission related, but it's seems odd that the problem resolves itself after a few minutes. I'm driving in D1 (the position next to low)... also tried low.