I acquired a 71 Diesel PS a few years back in non running condition. Supposedly had sat for maybe 8+ years. Got it running after a cleaning and re seal of the injector pump. Changed hyd filters and pulled sump screen which was nearly pristine. Oil and filters have been completely changed twice since then. From day 1 there would be random times that reverse would not engage. Usually first thing in the morning, then once it decided to engage it would be good the rest of the day. Some days you could start it in the morning and reverse works right away. Well now I think it has gone into permanent limp mode. Rigged up a pressure gauge and took some system pressure and B3 pressure checks. System pressure is right around 160# in all forward gears, forward neutral, and neutral. In reverse neutral and all reverse gears, system pressure drops to about 125#. Testing B3 yields only 20# in neutral reverse and all reverse gears. Wondering what the Deere Doctors here have to say. The prior random engagement seems rather puzzling. Thank you.