changed filter and neutral safety switch with no luck.. when I put it in reverse or park it only revs up to 2000 rpm and just sits there like I have foot on brake. All forward gears work and neutral is non existent, it's now drive. When I put it in first gear it drives and continues to shift to other gears and when I let off it does slow right down at lower speed and jolt you forward as it should.. any one have any idea what the possible issue is?