Branson 5220c PTO clutch and pressures

[94ram15004x4]

Last year my PTO clutch started slipping. I tried reading pressure on the back of the transmission where the hydraulic lines go in and had zero psi. Port g2 on the pto valve block and the port in the back of the transmission have the same pressures. The next step was tearing apart. I was able to lift the cab a few inches and support it, just pulling the back bolts out. this gave me enough clearance to pull the 3-point piston off. you need to do this to get the assembled PTO gears and clutch back in. I was able to sneak it all out but it disassembled. Branson put a detent bolt that holds the shift fork in the left axle. I decided to fight it and not tear all that apart. The clutch was pretty straightforward, took a bit to install because of wiggling all the gears and shift fork in but overall not a horrible job. I think I had a total of 8 hours over a few days to tear it down and put it back together. The seat needs to be removed inside the cab to gain access to bolts. I was able to pick the 3-point cylinder up via ratchet straps and slid it on a motorcycle lift table, it is heavy and not in a great spot to lift. I couldn't get a cherry picker in there so had to improvise. Got it all back together, refilled it with oil, over 10 gallons, and ran to check. The pressure was at 130 and cycling about 100 psi. It calls for 227 psi on the European model, so that's what i went with. not sure why the US one is lower. I tried running it a few days later and the PTO did nothing again. back to checking pressures, and found zero psi. I pulled the lines off the back of the transmission and had zero flow. According to the diagrams, the flow is reversed to energize the clutch. So tear into the valve block. Yes, I tested the solenoid first to make sure that is operating. I had good voltage, and good ground, could hear it clicking, and could feel it magnetized. After getting the valve block on the bench I hooked air to it to see where the flow was going. the shinny part is where it bolts to the transmission and that is the return for the system. it was dumping out of the sequencing valve (#2) into the transmission. I cleaned everything and replaced the o-rings. not sure if there was junk in one of the orifices or a plugged passage. but either way, I got it working. all the little set screws are lock-tightened in and are a bastard to remove. put it back in, and checked the pressure, and it's good to go. so the operation of this, the sequencing valve- controls the pressure to the pto clutch pack. the solenoid valve reversed the flow and energized the pto. the modulation valve (#3) controls how soft of a start the PTO is. I couldn't find information on how to set the modulation valve, so I did it to where it was a smooth start and a few seconds delay. The picture of the bag is the part number for the metric thread on the back of the transmission. this is a test port going to a #4 jic.

Hope this helps someone as I didn't find a lot of information on the web

 

[Boswell]

Nice write-up. Thanks for sharing.