dont know a whole lot about the jd utility tractors so this is wy I am asking.80 year old neighbor has a 2640 with IPTO and with out a hi lo.He said pto quit while mowing so I ran over to look at it.checked pressure at pto and it is only 100 at 2000 rpm. I think it should be at least 140.All other hydraulics work like they should but if you have the gauge hooked up and pto on and move either one of the scv levers to move the loader the pto pressure goes up to 150 then back down to 100.I was wondering if pto disks get thin will that cause this? Or more like a internal leak? I would like to help the old man out so he doesnt get ripped off at dealer.Any thought on this let me know.I like to get some ideas before I tear something apart.I have done that in the past and I always find the problem but the more help before the teardown is beter.Thanks