This is quite timely as I have a 2006 Vio27 with near the same issue. I had an issue with blade down pressure and weak travel motors. I tested and found the joint bypassing, so removed and re sealed it. The blade works great now, and there was some improvement in the strength of the travel motors but it just doesn’t chug along like I’d expect it to.
I removed the case drain lines for each motor and check the stalled bypass through the entire rotation of the motor (or where I could lock it up/index it on the sprocket) The service manual does not give an expected flow rate, but after stalling the motor for 1 minute I have maybe a liter of fluid. Both motors bypass about the same amount. I am no pump guy, but this seems ok to me? Please correct me if I’m wrong.
I’ve re sealed and set the system reliefs to 2900lbs as the book specs out. I have not measured pump pressure, however I would be lead to believe that if the system reliefs operate as they should then the pump would not be the issue? Once again, please correct me if that is the wrong assumption to make.
The symptoms I have are weak travel, an inability to track up a hill at high speed (as in, high speed selection makes no difference when traversing up a hill) and the boom will not pitch the machine all the way back without help from other functions.
The boom, bucket and left side travel motor are supplied from P1, the other functions from P2.
I am starting to lean towards the main control valve which splits the valve bank. Both travel slices are on either side of the main control valve slice, and run off of the system reliefs. I have plenty of pressure, but I seem to lack flow? However in my head, if I lacked flow I wouldn’t be able to make pressure. Again, please correct me in this respect too.
Long winded but hopefully someone may have a bit of insight.