The torque converter control valve on my Case 580B does not reduce the torque converter pressure sufficiently to shift gears without grinding. Once in gear, the tractor moves forward and reverse beautifully with about 140 lbs. hydraulic pressure. I have adjusted the cam control to the extent that the valve rod bottoms out in the valve. The pressure remains at 10 psi with the rod completely in the housing. If I move the forward/reverse lever out of the neutral position while depressing the clutch pedal (rod bottomed out in the valve), the pressure drops to zero and the gears can be shifted without grinding. Can anyone point me in the right direction?
I'm no expert on these valves but, my neighbor just bought a CK and was having some issues with low pressure in reverse, so I was doing some research..To my understanding that spool controls pressure to the FNR spool .It's just a spool without a spring behind it, so if it's bottomed out it's not in the position it should be and is probably diverting your fluid and not totally interrupting the flow so you can shift...Search Everyday Projects channel circa 2-25-21 and GRT Ranch Adventures on You Tube for a better understanding of how that valve/ spools actually function, the GRT Adventures covers a bunch of stuff on his 580B, it may be helpful...good luck...Stinky
That is an awesome video that you found, Stinky. I was surprised that he has not drilled the transmission case to get access to the screen on the pick-up tube. Everyday Adventures has a video on YouTube that describe repairing the control valve.
Apparently he hasn't been turned onto this forum yet , the other channel with the other very informative valve rebuild is Everyday Projects, that guy has flow charts and everything.. I looked up the everyday adventures channel to maybe score more info and something tells me that guy isn't a backhoe enthusiast...
I think it is amazing that people like those two and many others take the time to create and post those videos on YouTube.
Tinkerer, you and your NASA hard drive do almost the same thing on a daily basis and while you are a keeper of knowledge, they are VLOGers of knowledge...