I bought a 3012 Ingersoll with a bad rod and fixed that. Tractor runs awesome. When I was putting around with it to break it in I noticed how smooth the Hydriv worked compared to my other Cases. It didn't jump, it was real smooth. Fast forward a couple weeks later when I was driving it again the tractor wouldn't move until the lever to go forward and reverse was at about 3/4 of the way. It does this in forward and reverse. I checked the linkages on the control valve and they have very little slop, maybe less than 1/8 inch. When I pulled the engine before the rebuild I drained the hydriv oil by pulling off the big rubber hose down by the pump. I zip tied bags around the open hose and fitting it goes on to so nothing could get in there. After the engine was in I put Shell Rotella T 15w40 in the Hydriv reservoir about 5-6 inches down from the top and rechecked it after filling the lines. What do you guys think the problem may be? Here's a picture of where he tractor starts to move in both directions. I can get more picture and video of stuff if you need it.