I have been having hydraulic problems with this tractor for a few months involving no hydraulic pressure to my rear implement and losing power steering. Recently, I was pulling offset disks when our 4430 slowed down to a stop. At this point I was able to raise the disks extremely slowly at the full hydraulic speed. With the disks in the air the tractor was unable to move in any gear. Once I opened the cab I was able to hear the horrible knock coming from the hydraulic pump in the front of the tractor. Was told the pump was the problem from our local dealer and I removed the pump and had them rebuild it. Installed the rebuilt pump. First thing I did was raise the disks which now moved extremely fast up and down. I had good brake pressure and power steering. Put the tractor in gear and it just rolled at a speed slower than the slowest gear and it moved at the same speed no matter the gear selection. I do have forward and reverse but it moves at the same speed in each direction. It has a brand new hydraulic fluid, brand new hydraulic filter, and I cleaned the screen in front of the axle. Kinda stumped at this point. My only guess is maybe their is air trapped somewhere? Any help would be appreciated.