I have a 1565. We were running a broom and broke the u-joint on the driveshaft. We repaired it, and since then the PTO won't completely shut off. If you set the brush down, it will stop spinning. But when it's in the air it turns. When you turn the PTO switch is turned on it functions as normal. The machine does start and run fine with the PTO switch off, even though the shaft is turning.
To reiterate, any time we turn the machine on, the PTO turns, although not at full speed. With the PTO switch on it functions as normal.
I am not certain that breaking the driveshaft is related, but that's when the change started so I am guessing it is related.
2 things could have happened. The pto brake spring is broken or oil is bypassing in either the pto valve or pto clutch basket assy. The pto clutch/brake assy is internal in the transmission. The pto valve body is external. A couple of quick pressure checks by the dealer will pinpoint the exact trouble. No more than an hour labor for diag.