My car seems to get harder to get into gear the longer I drive it. In other words, I can take off and probably drive 20 miles or so and it shifts fine. After that it seems as it gets harder to get it to go thru the gears. Could it be maybe cause the clutch is out of adjustment, I imagine it still has the original quadrant and cable and such, I'm planning on replacing that, or does it sound like a transmission problem? THanks for input.