L3430 HST not operating

[mfgkenney]

Hello all,
Started digging into my other government surplus tractor. So far it only moves in low range with the engine at maximum rpms. It's movement is jerky, especially moving forward. The 3pt and front hydraulics work as designed, and my hst filter is new. Oil level is good. Any ideas of what I'm dealing with, based on the videos below and my description? When I get a chance, I am going to check my charge pump pressure.

Thanks,
Matt https://youtube.com/shorts/nNo15fdY2OA?si=rSrNQE4X8wPveWPK

https://youtube.com/shorts/vSzSI_hV4fc?si=M_I-x6qoCfMxn7jd

https://photos.app.goo.gl/snARj7bribBBFvhLA

 

[North Idaho Wolfman]

See what the PTO is doing when you try and move it in high range.
If it stops spinning you have a toasted clutch!

 

[mfgkenney]

So i tested the pto in high range, and it seemed to operate as normal. I did the charge relief valve test and high pressure relief valve test. My charge relief valve pressure was high, at just below 1200 psi (factory spec 327-355psi) and my high pressure relief valve came in low at 4200 psi (factory spec 4856-5262psi). I didn't see any procedure for testing my charge pump pressure in the wsm, nor could I find a procedure for shimming the valves. It talks about the pressure difference for shimming, but it doesn't say whether or not the pressure change would increase or decrease my pressure. I would think that it would decrease the pressure as it is adding a pre-load to the spring. Does that make sense? Any thoughts?

Thanks,
Matt

 

[ruger1980]

1200psi charge pressure is extremely high. Are you certain the servo on the pump is not stroking the pump slightly when you are measuring charge pressure? Try rocking the travel pedal to see if pressure drops to a more correct number. It is best to have a gauge in each port that way you can see what pump output and charge pressure doing when trying to travel. If charge pressure drops off significantly that shows you have severe internal leakage.

 

[mfgkenney]

1200psi charge pressure is extremely high. Are you certain the servo on the pump is not stroking the pump slightly when you are measuring charge pressure? Try rocking the travel pedal to see if pressure drops to a more correct number. It is best to have a gauge in each port that way you can see what pump output and charge pressure doing when trying to travel. If charge pressure drops off significantly that shows you have severe internal leakage.

I will give that a try. I will also try to piece together another test rig, but if I recall, access to the other port will be a challenge due to the cab or piping or something. I will take another look when I get a chance, and piece together another test rig.

Thanks,
Matt

 

[ruger1980]

Please post how you are connecting your gauges and to which ports. Also what gauges are you using?

 

[mfgkenney]

Please post how you are connecting your gauges and to which ports. Also what gauges are you using?

I'm using p2, p1 appears obstructed by something (see pic), possibly the cab floor which is pretty crunchy. The tractor was used for plowing snow at a hospital, and for spreading rock salt. Unfortunately they never heard of a pressure washer.

As for my gauge setup, I have a couple adapters connected to a 1/4" hose, connected to a quick connect coupling to a gauge manufactured by winters. I used a 0-3000 psi gauge for the charge relief pressure and a 0-10000 for the high relief pressure test.

I didn't get a chance to retest today, after I got home from my real job, I helped a neighbor with his hay (800 square bales from about 10 acres, great crop this year!) And then had to run off to an appointment. I will try and get to it this weekend.

Thanks for the help,

Matt