Our 2007 H45D is stuttering or vibrating a little on the initial start of motion in both forward and reverse. once the machine is moving it seems to go away until you turn one direction. The local repair shop tells us that it could be the drive motor on the right side, but the machine is not that old and only has less that 2000 hrs on it. How can one be sure of this because they are not 100% sure themselves.