There is nothing anywhere on or in the tractor outside the pump that can cause the main pump to leak other then mechanical damage from debris in the oil or extreme overheating.
The pump has its own protection system so it cannot exceed PSI limits.
A leaking loader valve will just result in oil leakage and that is all. That is, unless you have a convertible valve which Deere used on some loaders in the 80s-90s. A convertible valve works with an open-center or closed-center system. Your Deere has a closed-center. If that valve is a convertible type, and the conversion plug in it blows its seals - then the hydraulics work awful and overheat. Plus the tractor tends to get very hard to start and burns up starter motors.