M7040 shuttle problem

[Mark Robke]

Exactly, you read what is going on with a correctly operating valve, so any deviation will point to the problem, be it the proportionally reducing valve, the shuttle valve, the inching valve and so on.
It's a testable process of elimination.
Do all the pressure tests in all possible test scenarios and it will point to the problem or problems if there are multiple issue.
Testing these kinds of issues is a simple matter of you will see this pressure or the lack of pressure (bad behavior) and it will be caused by this fault (bad part).

Thanks for your insight- I was mostly going by page 3-S13 (pressure readings) - thinking, 'does bad pressure readings indicate a problem in the valve, or elsewhere'? According to your logic then, bad readings would indicate the shuttle valve is bad. I don't believe it is rebuildable, and was not intended to be disassembled. My hunch all along is that something is sticking only when it gets hot-so we shall see I hope! Good pressure readings would indicate my problem is elsewhere, not the valve. Thanks for all your time. When I have time, after hay is done, I will dive deeper into this, and I will let you all know what I find. Mark.