Mowing Massey Ferguson135 PTO Turning Slow

[Lard29]

Went to brush hog with my Massey 135 and the PTO wasn't spinning as fast as it should "maybe half as fast". When I placed the tractor into low gear, it spun even faster. When the selector switch was on engine, it wouldn't work at all. If it was in neutral or ground, it would spin, just slowly. I did a hydraulic oil change and cleaned the filter behind the selector switch, but I'm almost positive I placed the switch back in correctly because it will go through Ground, neutral and engine.

 

[UpstateJohn]

I've got a similar issue in my Massey 135. How did you solve your problem? I wasn't clear if the oil change made any difference. Thanks!