1552 PTO problems

DMF · Sep 13, 2015

I have a problem with the PTO on my MF 1552. I turn the switch on and everything on the dash indicates it's on snd working. The PTO light comes on, the RPMs appear to indicate as well but the shaft doesn't turn. The shaft engages and disengages with the selector lever; when it's in neutral I can spin the shaft, when I move it to 540 the shaft stops turning so I don't believe the shaft itself is broken. It's almost like the switch doesn't actuate the PTO clutch. Can anyone tell me how to troubleshoot it? Thanks!

TSO · Sep 14, 2015

Just a guess... Check for a blown fuse. That switch electronically activates the PTO.

DMF · Sep 14, 2015

My manual doesn't show a fuse related to the PTO (?) but I checked all the fuses in the cab and the slow blow fuses under the hood and they all seem fine...

TSO · Sep 14, 2015

DMF said:
My manual doesn't show a fuse related to the PTO (?) but I checked all the fuses in the cab and the slow blow fuses under the hood and they all seem fine...

Ok. I wonder if there's a relay that could have fried.

There's probably also a linkage that would engage or disengage the PTO clutch. Possibly that linkage is damaged, or stuck... Debris maybe?

These are all guesses...

DMF · Sep 14, 2015

I'm thinking a relay or solenoid as well but I don't even know where to look...

TSO · Sep 14, 2015

Check AGCO parts online. They have full diagrams available of our machines.

DMF · Sep 16, 2015

So I worked on this with a friend who is a Deere mechanic until 10:30 last night. The solenoids that actuate the PTO soft start and the PTO clutch both were receiving 12 volts when activated, but nothing happens. At the rear of the solenoid is a set screw with a jam nut. We tried turning the screw in with no luck. He ended up taking the screw out and depressing the stem with a screw driver and the PTO started turning; progress! But now it wouldn't turn off...

We pulled the solenoid and stem out of the valve body and it seemed very stiff. We swapped solenoid/stem assemblies from the soft start to the PTO clutch and it worked! The PTO turns on and off with the switch. We have no idea why it failed; there was no visible external damage to it....?

Now the problem is getting a replacement. AGCO's part books on-line are cryptic at best; I can't even find anything under the PTO sections that show the valve/stem/solenoid assembly.

This is a picture of one that is similar but mine does not have the attachment flange; it just unscrews from the valve body and the wires come out the back side:
http://i01.i.aliimg.com/wsphoto/v0/...point-for-Caterpillar-E320-E320B-121-1490.jpg

Any help in finding this would be appreciated!