I'm not very mechanical savvy still learning. I took my jeep back to mechanic today after i had a new clutch installed on it because i noticed it was slipping through the gear when in first on my driveway which is slightly steep. the mechanic told me the clutch is doing its job, its my decreasing engine compression that is causing it to slowly slip because he saw the fan move and the engine shake a little as it rolled back slowly on a hill. its not a complete roll it will slowly edge back then stop and jeep will shake a little then slowly roll back and repeat. i was wonder if this is legitimate or am i getting scammed?