On initial startup there seems to be a strain on the engine and enough drive to the wheels that on level ground with the bucket up it will move. Control levels are centered when this happens. Wiggling them does not seem to change the issue. After a minute or so its more or less fine. Sometimes during operation it will do it also. Sometimes while operating it will almost seem to stall the engine and again wiggling the controls does not seem to have a direct effect but most of the time it corrects itself and may be fine for 30seconds or an hour. Normally the left side is faster. When I go forward from reverse the left side is slower unless I quickly return to center and back to full forward then it will be back to faster as usual. Machine has one resivor with fresh ATF (what the manual recomends). Seperate drive pumps driven with a common belt with no signs of slipage. Loader is driven with its own pump. Filters are on the pickup side for each pump and are new with the proper micron size according to manual. Im thinking that the basic pump and motor parts are fine since it seems to have plenty of power. I am wondering if it could be the check valves? If the check valve was not seated well it looks like the charge pressure (could be 150psi) may be trying to drive the motor? The check vlaves are easy to get to, just waiting for my dealer to tell me if they are still available from mustang. I dont think it would be the charge relief and that one may require me to remove the pumps to get to them. What do you guys think? This picture is my pump but I dont think my motor has the return line like the one in the picture.
