I recently installed a rebuilt right side drive motor but I am having hydraulic issues that are puzzling. When I first put the drive motor on it tested fine in both forward and reverse. I ran it a good deal in both directions and it seemed to work fine. Installed the track and proceeded to attempt to work the air out of the lift arm. I was not having any luck so I thought I would drive the machine outside and continue to work the air out of the system. The machine drove out side fine and I backed into a nice spot, but when I decided to move it ahead a few more feet the machine decided it was going to continue going forward and not stop. I have the machine up on blocks now and am puzzled as to why the hydraulics are behaving so oddly. When I first start the machine (after it has been sitting for a while) the drive motors will work in the reverse direction but not in the forward direction, but after the machine has been running for a while the drives start to move forward and accelerate until moving at full speed. The drives at this point will no longer operate in the reverse. At best they will slow down or stop when they are moving slowly but after the drives reach full speed they will not respond reversing the control. I have never been able to get the lift arm function working either. Anybody have any ideas? If it was just one drive acting this way I would think it was the drive I installed, but with both drives acting exactly the same I am puzzled. I should note that the machine has pilot style controls. Left hand works the drives; right hand operated lift arm and bucket. Any and all help will be greatly appreciated. Thank you.