I am having a problem with my car when I put the transmission in reverse. When I put it in reverse the car will start to go backwards like it is in the reverse gear but if I step on the accelerator the engine revs up but the speed does not until it hits a point then it jerks the car when it catches. I checked the transmission fluid and it is at the correct place on the dip stick. It first happened when I was on a hill facing downward. I put the car in reverse and it did not want to back up the hill so I stepped on the accelerator and it finally engaged with a jerking motion. Does anyone have any ideas?