The two clutch disks are not separately adjustable on these tractors. When the travel disk is worn thin enough to stop driving, travel can be restored by adjusting the external pedal linkage. But the pto clutch may no longer disengage, except with the lever.
With the pto clutch always engaged operation is a bit tricky. Put the pto lever in N, move to where you'll be using the implement, shut off the engine, shift the lever to L, and restart the engine with implement engaged. Use the lever to stop the pto if needed.
Many L345's are operated this way until they're split for travel clutch replacement. My L345 has needed a travel clutch for a few years. I use it with a sickle mower or pto generator, so it's ok to live with. Take care, Dick B