Hi, I have a 743 that I just replaced the whole drive pump assembly, that I got from LPS. Also had got the rebuild kits for the drive motors. Got the new pump installed and the motors rebuilt and back in. Started it up and it didn't want to move really and what little it did was opposite of the direction of the controls. Went through some threads on here and found to check my port block. Pulled it out went through it with not finding much. But I did tighten the fitting with spring and poppet for the charge pressure tighter then it was. Now the machine moves but still opposite. I did hook a pressure gauge to the charge line but doesn't look like there is much pressure there, since my gauge is marked at 100psi increments. My serial is 22588 so I have the port block on the side not the one on top of the pump with the brass filter.